<PAGE>   1
                                                                     Exhibit 4.6





                          PASS THROUGH TRUST AGREEMENT

                           Dated as of October 6, 1998

                                     between

                           AMERICA WEST AIRLINES, INC.

                                       and

                            WILMINGTON TRUST COMPANY,

                                   as Trustee

           America West Airlines Pass Through Trust, Series 1998-1B-O

            7.12% Initial Pass Through Certificates, Series 1998-1B-O
           7.12% Exchange Pass Through Certificates, Series 1998-1B-O
<PAGE>   2
Reconciliation and tie between America West Airlines Pass Through Trust
Agreement, Series 1998-1B-O dated as of October 6, 1998, and the Trust Indenture
Act of 1939. This reconciliation does not constitute part of the Pass Through
Trust Agreement.

Trust Indenture Act                                       Pass Through Trust
   of 1939 Section                                        Agreement Section
 310(a)(1)                                                   7.08
    (a)(2)                                                   7.08
 312(a)                                                      3.05; 8.01; 8.02
 313(a)                                                      7.06; 8.03
 314(a)                                                      8.04(a),(c) & (d)
    (a)(4)                                                   8.04(e)
    (c)(1)                                                   1.02
    (c)(2)                                                   1.02
    (d)(1)                                                   7.13; 11.01
    (d)(2)                                                   7.13; 11.01
    (d)(3)                                                   2.01
    (e)                                                      1.02
 315(b)                                                      7.02
 316(a)(last sentence)                                       1.04(c)
         (a)(1)(A)                                           6.04
         (a)(1)(B)                                           6.05
         (b)                                                 6.06
         (c)                                                 1.04(e)
 317(a)(1)                                                   6.03
    (b)                                                      7.13
 318(a)                                                     12.06
<PAGE>   3
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
SECTION                                                                                                        PAGE
<S>                                                                                                            <C>
ARTICLE I  DEFINITIONS............................................................................................2
         Section 1.01.     Definitions............................................................................2
         Section 1.02.     Compliance Certificates and Opinions..................................................13
         Section 1.03.     Form of Documents Delivered to Trustee................................................14
         Section 1.04.     Directions of Certificateholders......................................................14

ARTICLE II  ORIGINAL ISSUANCE OF CERTIFICATES; ACQUISITION OF EQUIPMENT NOTES....................................16
         Section 2.01.     Issuance of Certificates; Acquisition of Equipment Notes..............................16
         Section 2.02.     Withdrawal of Deposits................................................................17
         Section 2.03.     Acceptance by Trustee.................................................................17
         Section 2.04.     Limitation of Powers..................................................................17

ARTICLE III  THE CERTIFICATES....................................................................................17
         Section 3.01.     Title, Form, Denomination and Execution of Certificates...............................17
         Section 3.02.     Restrictive Legends...................................................................19
         Section 3.03.     Authentication of Certificates........................................................21
         Section 3.04.     Transfer and Exchange.................................................................21
         Section 3.05.     Book-Entry Provisions for Restricted Global Certificates and Regulation S
                           Global Certificates...................................................................22
         Section 3.06.     Special Transfer Provisions...........................................................24
         Section 3.07.     Mutilated, Destroyed, Lost or Stolen Certificates.....................................27
         Section 3.08.     Persons Deemed Owners.................................................................27
         Section 3.09.     Cancellation..........................................................................27
         Section 3.10.     Temporary Certificates................................................................27
         Section 3.11.     Limitation of Liability for Payments..................................................28
         Section 3.12      ERISA Restrictive Legend..............................................................28

ARTICLE IV  DISTRIBUTIONS; STATEMENTS TO CERTIFICATEHOLDERS......................................................29
         Section 4.01.     Certificate Account and Special Payments Account......................................29
         Section 4.02.     Distributions from Certificate Account and Special Payments Account...................29
         Section 4.03.     Statements to Certificateholders......................................................30
         Section 4.04.     Investment of Special Payment Moneys..................................................32

ARTICLE V  THE COMPANY...........................................................................................32
         Section 5.01.     Maintenance of Corporate Existence....................................................32
         Section 5.02.     Consolidation, Merger, etc............................................................32

ARTICLE VI  DEFAULT..............................................................................................33
         Section 6.01.     Events of Default.....................................................................33
         Section 6.02.     Incidents of Sale of Equipment Notes..................................................35
         Section 6.03.     Judicial Proceedings Instituted by Trustee; Trustee May Bring Suit....................36
</TABLE>
<PAGE>   4
<TABLE>
<CAPTION>
SECTION                                                                                                        PAGE
<S>                                                                                                            <C>
         Section 6.04      Control by Certificateholders.........................................................36
         Section 6.05.     Waiver of Past Defaults...............................................................36
         Section 6.06.     Right of Certificateholders to Receive Payments Not to Be Impaired....................37
         Section 6.07.     Certificateholders May Not Bring Suit Except Under Certain Conditions.................37
         Section 6.08.     Remedies Cumulative...................................................................38

ARTICLE VII  THE TRUSTEE.........................................................................................38
         Section 7.01.     Certain Duties and Responsibilities...................................................38
         Section 7.02.     Notice of Defaults....................................................................39
         Section 7.03.     Certain Rights of Trustee.............................................................39
         Section 7.04.     Not Responsible for Recitals or Issuance of Certificates..............................40
         Section 7.05.     May Hold Certificates.................................................................40
         Section 7.06.     Money Held in Trust...................................................................40
         Section 7.07.     Compensation and Reimbursement........................................................40
         Section 7.08.     Corporate Trustee Required; Eligibility...............................................42
         Section 7.09      Resignation and Removal; Appointment of Successor.....................................42
         Section 7.10.     Acceptance of Appointment by Successor................................................43
         Section 7.11.     Merger, Conversion, Consolidation or Succession to Business...........................44
         Section 7.12.     Maintenance of Agencies...............................................................44
         Section 7.13.     Money for Certificate Payments to Be Held in Trust....................................45
         Section 7.14.     Registration of Equipment Notes in Name of Subordination Agent........................45
         Section 7.15.     Representations and Warranties of Trustee.............................................46
         Section 7.16.     Withholding Taxes, Information Reporting..............................................46
         Section 7.17.     Trustee's Liens.......................................................................47
         Section 7.18.     Preferential Collection of Claims.....................................................47

ARTICLE VIII  CERTIFICATEHOLDERS' LISTS AND REPORTS BY TRUSTEE...................................................48
         Section 8.01.     The Company to Furnish Trustee with Names and Addresses of Certificateholders.........48
         Section 8.02.     Preservation of Information; Communications to Certificateholders.....................48
         Section 8.03.     Reports by Trustee....................................................................48
         Section 8.04.     Reports by the Company................................................................48

ARTICLE IX  SUPPLEMENTAL AGREEMENTS..............................................................................49
         Section 9.01.     Supplemental Agreements Without Consent of Certificateholders.........................49
         Section 9.02.     Supplemental Agreements with Consent of Certificateholders............................50
         Section 9.03.     Documents Affecting Immunity or Indemnity.............................................52
         Section 9.04.     Execution of Supplemental Agreements..................................................52
         Section 9.05.     Effect of Supplemental Agreements.....................................................52
         Section 9.06.     Conformity with Trust Indenture Act...................................................52
         Section 9.07.     Reference in Certificates to Supplemental Agreements..................................52
</TABLE>


                                       ii
<PAGE>   5
<TABLE>
<CAPTION>
SECTION                                                                                                        PAGE
<S>                                                                                                            <C>
ARTICLE X  AMENDMENTS TO INDENTURES AND FINANCING DOCUMENTS......................................................52
         Section 10.01.    Amendments and Supplements to Indentures and Financing Documents......................52

ARTICLE XI  TERMINATION OF TRUST.................................................................................53
         Section 11.01.    Termination of the Trust..............................................................53

ARTICLE XII  MISCELLANEOUS PROVISIONS............................................................................55
         Section 12.01.    Limitation on Rights of Certificateholders............................................55
         Section 12.02.    Certificates Nonassessable and Fully Paid.............................................56
         Section 12.03.    Notices...............................................................................56
         Section 12.04.    Governing Law.........................................................................57
         Section 12.05.    Severability of Provisions............................................................57
         Section 12.06.    Trust Indenture Act Controls..........................................................57
         Section 12.07.    Effect of Headings and Table of Contents..............................................57
         Section 12.08.    Successors and Assigns................................................................58
         Section 12.09.    Benefits of Agreement.................................................................58
         Section 12.10.    Legal Holidays........................................................................58
         Section 12.11.    Counterparts..........................................................................58
         Section 12.12.    Intention of Parties..................................................................58
</TABLE>

Exhibit A - Form of Certificate
Exhibit B - Form of Certificate to Request Removal of Restricted Legend
Exhibit C - Form of Certificate to be Delivered by an Institutional Accredited
            Investor
Exhibit D - Form of Assignment and Assumption Agreement
Exhibit E - Form of Notice to Withholding Agent


                                      iii
<PAGE>   6
                          PASS THROUGH TRUST AGREEMENT

                  This PASS THROUGH TRUST AGREEMENT, dated as of October 6, 1998
(the "Agreement"), between AMERICA WEST AIRLINES, INC., a Delaware corporation,
and WILMINGTON TRUST COMPANY, as Trustee, is made with respect to the formation
of America West Airlines Pass Through Trust, Series 1998-1B-O and the issuance
of 7.12% America West Airlines Pass Through Trust, Series 1998-1B-O Pass Through
Certificates representing fractional undivided interests in the Trust.

                                   WITNESSETH:

                  WHEREAS, the Company has obtained commitments from AVSA for
the delivery of certain Aircraft;

                  WHEREAS, the Company intends to finance (or refinance) the
acquisition of the Aircraft either (i) through separate leveraged lease
transactions in which the Company will lease such aircraft (collectively, the
"Leased Aircraft") or (ii) through separate secured loan transactions in which
the Company will own such Aircraft (collectively, the "Owned Aircraft");

                  WHEREAS, in the case of each Leased Aircraft, each Owner
Trustee, acting on behalf of the corresponding Owner Participant, will issue
pursuant to an Indenture, on a non-recourse basis, three series (or, subject to
satisfaction of certain preconditions contained in the Note Purchase Agreement,
four) of Equipment Notes in order to finance a portion of its purchase price of
such Leased Aircraft;

                  WHEREAS, in the case of each Owned Aircraft, the Company will
issue pursuant to an Indenture, on a recourse basis, three (or, subject to
satisfaction of certain preconditions contained in the Note Purchase Agreement,
four) series of Equipment Notes to finance a portion of the purchase price of
such Owned Aircraft;

                  WHEREAS, the Trustee, upon execution and delivery of this
Agreement, hereby declares the creation of the Trust for the benefit of the
Certificateholders, and the initial Certificateholders, as the grantors of the
Trust, by their respective acceptances of the Certificates, join in the creation
of this Trust with the Trustee;

                  WHEREAS, all Certificates to be issued by the Trust will
evidence fractional undivided interests in the Trust and will convey no rights,
benefits or interests in respect of any property other than the Trust Property
except for those Certificates to which an Escrow Receipt has been affixed;

                  WHEREAS, the Escrow Agent and the Initial Purchasers have
contemporaneously herewith entered into an Escrow Agreement with the Escrow
Paying Agent pursuant to which the Initial Purchasers have delivered to the
Escrow Agent the proceeds from the sale of the Certificates and have irrevocably
instructed the Escrow Agent to withdraw and pay funds from such proceeds upon
request and proper certification by the Trustee to purchase Equipment Notes;
<PAGE>   7
                                      -2-


                  WHEREAS, the Escrow Agent on behalf of the Certificateholders
has contemporaneously herewith entered into a Deposit Agreement with the
Depositary under which the Deposits referred to therein will be made and from
which it will withdraw funds to allow the Trustee to purchase Equipment Notes
from time to time prior to the Delivery Period Termination Date;

                  WHEREAS, pursuant to the terms and conditions of this
Agreement and the Note Purchase Agreement, upon or following delivery of an
Aircraft, the Trustee on behalf of the Trust, using funds withdrawn under the
Escrow Agreement, may purchase an Equipment Note having the same interest rate
as, and final legal distribution date not later than the final Regular
Distribution Date of, the Certificates issued hereunder and shall hold such
Equipment Note in trust for the benefit of the Certificateholders;

                  WHEREAS, to facilitate the sale of Equipment Notes to, and the
purchase of Equipment Notes by, the Trustee on behalf of the Trust, the Company
has duly authorized the execution and delivery of this Agreement as the
"issuer", as such term is defined in and solely for purposes of the Securities
Act, of the Certificates to be issued pursuant hereto and as the "obligor", as
such term is defined in and solely for purposes of the Trust Indenture Act of
1939, as amended, with respect to all such Certificates and is undertaking to
perform certain administrative and ministerial duties hereunder and is also
undertaking to pay the ongoing fees and expenses of the Trustee;

                  WHEREAS, all of the conditions and requirements necessary to
make this Agreement, when duly executed and delivered, a valid, binding and
legal instrument, enforceable in accordance with its terms and for the purposes
herein expressed, have been done, performed and fulfilled, and the execution and
delivery of this Agreement in the form and with the terms hereof have been in
all respects duly authorized; and

                  WHEREAS, upon issuance of the Exchange Certificates, if any,
or the effectiveness of the Shelf Registration Statement, this Agreement, as
amended or supplemented from time to time, will be subject to the provisions of
the Trust Indenture Act of 1939, and shall, to the extent applicable, be
governed by such provisions;

                  NOW, THEREFORE, in consideration of the mutual agreements
herein contained, and of other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

                  Section 1.01. Definitions. For all purposes of this Agreement,
except as otherwise expressly provided or unless the context otherwise requires:

                  (1) the terms used in this Agreement, including in the
         recitals to this Agreement, that are defined in this Article have the
         meanings assigned to them in this Article, and include the plural as
         well as the singular;
<PAGE>   8
                                      -3-


                  (2) all other terms used herein which are defined in the Trust
         Indenture Act, either directly or by reference therein, or by the rules
         promulgated under the Trust Indenture Act, have the meanings assigned
         to them therein;

                  (3) all references in this Agreement to designated "Articles",
         "Sections", "Subsections" and other subdivisions are to the designated
         Articles, Sections, Subsections and other subdivisions of this
         Agreement;

                  (4) the words "herein", "hereof" and "hereunder" and other
         words of similar import refer to this Agreement as a whole and not to
         any particular Article, Section, SubSection or other subdivision; and

                  (5) unless the context otherwise requires, whenever the words
         "including", "include" or "includes" are used herein, it shall be
         deemed to be followed by the phrase "without limitation".

                  Affiliate: Means, with respect to any specified Person, any
         other Person directly or indirectly controlling or controlled by or
         under direct or indirect common control with such Person. For the
         purposes of this definition, "control" means the power, directly or
         indirectly, to direct the management and policies of such Person,
         whether through the ownership of voting securities or by contract or
         otherwise, and the terms "controlling" and "controlled" have meanings
         correlative to the foregoing.

                  Agent Members: Has the meaning specified in Section 3.05.

                  Agreement: Has the meaning specified in the initial paragraph
         hereto.

                  Aircraft: Has the meaning specified in the Note Purchase
         Agreement.

                  Aircraft Purchase Agreement: Has the meaning specified in the
         Note Purchase Agreement.

                  Applicable Delivery Date: Has the meaning specified in Section
         2.01(b).

                  Applicable Participation Agreement: Has the meaning specified
         in Section 2.01(b).

                  Assignment and Assumption Agreement: Means the assignment and
         assumption agreement substantially in the form of Exhibit D hereto to
         be executed and delivered in accordance with Section 11.01.

                  Authorized Agent: Means any Paying Agent or Registrar for the
         Certificates.

                  Avoidable Tax: Means a state or local tax (i) upon (w) the
         Trust, (x) the Trust Property, (y) Certificate-holders or (z) the
         Trustee for which the Trustee is entitled to seek reimbursement from
         the Trust Property, and (ii) which would be avoided if the Trustee were
         located in another state, or jurisdiction within a state, within the
         United
<PAGE>   9
                                      -4-


         States. A tax shall not be an Avoidable Tax if the Company or any Owner
         Trustee shall agree to pay, and shall pay, such tax.

                  AVSA: Means AVSA S.A.R.L., an affiliate of Airbus Industrie
         G.I.E.

                  Business Day: Means any day other than a Saturday, a Sunday or
         a day on which commercial banks are required or authorized to close in
         Phoenix, Arizona, New York, New York, Wilmington, Delaware or, so long
         as any Certificate is outstanding, the city and state in which the
         Trustee or any Loan Trustee maintains its Corporate Trust Office or
         receives and disburses funds.

                  Cedel: Means Cedel Bank societe anonyme.

                  Certificate: Means any one of the Initial Certificates or
         Exchange Certificates and any such Certificates issued in exchange
         therefor or replacement thereof pursuant to this Agreement.

                  Certificate Account: Means the account or accounts created and
         maintained pursuant to Section 4.01(a).

                  Certificate Purchase Agreement: Means the Purchase Agreement
         dated September 24, 1998 among the Initial Purchasers and the Company,
         as the same may be amended, supplemented or otherwise modified from
         time to time in accordance with its terms.

                  Certificateholder or Holder: Means the Person in whose name a
         Certificate is registered in the Register.

                  Class D Certificateholder: Means, at any time, any holder of
         one or more pass through certificates issued by the America West
         Airlines Pass Through Trust, Series 1998-1D, if and when established.

                  Company: Means America West Airlines, Inc., a Delaware
         corporation, or its successor in interest pursuant to Section 5.02, or
         (only in the context of provisions hereof, if any, where such reference
         is required for purposes of compliance with the Trust Indenture Act)
         any other "obligor" (within the meaning of the Trust Indenture Act)
         with respect to the Certificates.

                  Controlling Party: Has the meaning specified in the
         Intercreditor Agreement.

                  Corporate Trust Office: With respect to the Trustee or any
         Loan Trustee, means the office of such trustee in the city at which at
         any particular time its corporate trust business shall be principally
         administered.

                  Cut-off Date: Means the earlier of (a) the Delivery Period
         Termination Date and (b) the date on which a Triggering Event occurs.

                  Definitive Certificates: Has the meaning specified in Section
         3.01(e).
<PAGE>   10
                                      -5-


                  Delivery Date: Has the meaning specified in the Note Purchase
         Agreement.

                  Delivery Notice: Has the meaning specified in the Note
         Purchase Agreement.

                  Delivery Period Termination Date: Means the earlier of (a)
         November 30, 1999, or, if the Equipment Notes relating to all of the
         Aircraft (or Substitute Aircraft in lieu thereof) have not been
         purchased by the Trustee and the Other Trustees on or prior to such
         date due to any reason beyond the control of the Company and not
         occasioned by the Company's fault or negligence, January 31, 2000 and
         (b) the date on which Equipment Notes issued with respect to all of the
         Aircraft (or Substitute Aircraft in lieu thereof) have been purchased
         by the Trustee and the Other Trustees in accordance with the Note
         Purchase Agreement.

                  Deposits: Has the meaning specified in the Deposit Agreement.

                  Deposit Agreement: Means the Deposit Agreement dated as of
         October 6, 1998 relating to the Certificates between the Depositary and
         the Escrow Agent, as the same may be amended, supplemented or otherwise
         modified from time to time in accordance with its terms.

                  Depositary: Means ABN AMRO Bank N.V., acting through its
         Chicago branch.
         Direction: Has the meaning specified in Section  1.04(a).
        
                  Distribution Date: Means any Regular Distribution Date or
         Special Distribution Date as the context requires.

                  DTC: Means The Depository Trust Company, its nominees and
         their respective successors.

                  EBO Date: Means the date set forth on Schedule 1 to the Lease
         as the "EBO Date".

                  Equipment Notes: Means the equipment notes issued under the
         Indentures.

                  ERISA: Means the Employee Retirement Income Security Act of
         1974, as amended from time to time, or any successor federal statute.

                  ERISA Legend: Has the meaning specified in Section 3.12.

                  Escrow Agent: Means, initially, Wilmington Trust Company.

                  Escrow Agreement: Means the Escrow and Paying Agent Agreement
         dated as of October 6, 1998 relating to the Certificates, among the
         Escrow Agent, the Escrow Paying Agent, the Trustee and the Initial
         Purchasers, as the same may be amended, supplemented or otherwise
         modified from time to time in accordance with its terms.
<PAGE>   11
                                      -6-


                  Escrow Paying Agent: Means the Person acting as paying agent
         under the Escrow Agreement.

                  Escrow Receipt: Means the receipt substantially in the form
         annexed to the Escrow Agreement representing a fractional undivided
         interest in the funds held in escrow thereunder.

                  Euroclear: Means Morgan Guaranty Trust Company of New York,
         Brussels Office, as operator of the Euroclear System.

                  Event of Default: Means an Indenture Default under any
         Indenture pursuant to which Equipment Notes held by the Trust were
         issued.

                  Exchange Certificates: Means the pass through certificates
         substantially in the form of Exhibit A hereto issued in exchange for
         the Initial Certificates pursuant to the Registration Rights Agreement
         and authenticated hereunder.

                  Exchange Offer: Means the exchange offer which may be made
         pursuant to the Registration Rights Agreement to exchange Initial
         Certificates for Exchange Certificates.

                  Exchange Offer Registration Statement: Means the registration
         statement that, pursuant to the Registration Rights Agreement, is filed
         by the Company with the SEC with respect to the exchange of Initial
         Certificates for Exchange Certificates.

                  Final Legal Distribution Date: Means July 2, 2018.

                  Final Withdrawal: Has the meaning specified in the Escrow
         Agreement.

                  Final Withdrawal Date: Has the meaning specified in the Escrow
         Agreement.

                  Final Withdrawal Notice: Has the meaning specified in Section
         2.02.

                  Financing Documents: With respect to any Equipment Note, means
         (i) the Indenture and the Participation Agreement relating to such
         Equipment Note, and (ii) in the case of any Equipment Note related to a
         Leased Aircraft, the Lease relating to such Leased Aircraft.

                  Fractional Undivided Interest: Means the fractional undivided
         interest in the Trust that is evidenced by a Certificate.

                  Global Certificates: Has the meaning specified in Section
         3.01(d).

                  Global Exchange Certificate: Has the meaning specified in
         Section 3.01(f).

                  Indenture: Means each of the separate trust indentures and
         mortgages relating to the Aircraft, each as specified or described in a
         Delivery Notice delivered pursuant to the Note Purchase Agreement or
         the related Participation Agreement, in each case as the
<PAGE>   12
                                      -7-


         same may be amended, supplemented or otherwise modified from time to
         time in accordance with its terms.

                  Indenture Default: With respect to any Indenture, means any
         Event of Default (as such term is defined in such Indenture).

                  Initial Certificates: Means the certificates issued and
         authenticated hereunder substantially in the form of Exhibit A hereto
         other than the Exchange Certificates.

                  Initial Purchasers: Means, collectively, Morgan Stanley & Co.
         Incorporated, Donaldson, Lufkin & Jenrette Securities Corporation,
         Merrill, Lynch, Pierce, Fenner & Smith Incorporated and Salomon Smith
         Barney Inc.

                  Institutional Accredited Investor: Means an institutional
         investor that is an "accredited investor" within the meaning set forth
         in Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities
         Act.

                  Intercreditor Agreement: Means the Intercreditor Agreement
         dated as of October 6, 1998 among the Trustee, the Other Trustees, the
         Liquidity Provider, the liquidity provider relating to the Certificates
         issued under (and as defined in) each of the Other Pass Through Trust
         Agreements, and Wilmington Trust Company, as Subordination Agent and as
         trustee thereunder, as amended, supplemented or otherwise modified from
         time to time in accordance with its terms.

                  Investors: Means the Initial Purchasers together with all
         subsequent beneficial owners of the Certificates.

                  Issuance Date: Means the date of the issuance of the Initial
         Certificates.

                  Lease: Means, with respect to each Leased Aircraft, the lease
         between an Owner Trustee, as the lessor, and the Company, as the
         lessee, referred to in the related Indenture, as such lease may be
         amended, supplemented or otherwise modified in accordance with its
         terms.

                  Leased Aircraft: Has the meaning specified in the second
         recital to this Agreement.

                  Liquidity Facility: Means, initially, the Revolving Credit
         Agreement dated as of October 6, 1998 relating to the Certificates,
         between the Liquidity Provider and the Subordination Agent, as agent
         and trustee for the Trustee, and, from and after the replacement of
         such Agreement pursuant to the Intercreditor Agreement, the replacement
         liquidity facility therefor, in each case as amended, supplemented or
         otherwise modified from time to time in accordance with their
         respective terms.

                  Liquidity Provider: Means, initially, ABN AMRO Bank N.V.,
         acting through its Chicago branch and any replacement or successor
         therefor appointed in accordance with the Intercreditor Agreement.
<PAGE>   13
                                      -8-


                  Loan Trustee: With respect to any Equipment Note or the
         Indenture applicable thereto, means the bank or trust company
         designated as trustee under such Indenture, together with any successor
         to such trustee appointed pursuant thereto.

                  Material Adverse Tax Event: Has the meaning specified in
         Section 17.3(a)(4) of the Lease.

                  Non-U.S. Person: Means a Person that is not a "U.S. person",
         as defined in Regulation S.

                  Note Purchase Agreement: Means the Note Purchase Agreement
         dated as of October 6, 1998 among the Trustee, the Other Trustees, the
         Company, the Escrow Agent, the Escrow Paying Agent and the
         Subordination Agent, providing for, among other things, the purchase of
         Equipment Notes by the Trustee on behalf of the Trust, as the same may
         be amended, supplemented or otherwise modified from time to time, in
         accordance with its terms.

                  Notice of Purchase Withdrawal: Has the meaning specified in
         the Deposit Agreement.

                  Offering Circular: Means the Offering Memorandum dated
         September 24, 1998 relating to the offering of the Certificates and the
         certificates issued under the Other Pass Through Trust Agreements.

                  Officer's Certificate: Means a certificate signed, (a) in the
         case of the Company, by any Vice President or more senior officer of
         the Company or, (b) in the case of an Owner Trustee or a Loan Trustee,
         a Responsible Officer of such Owner Trustee or such Loan Trustee, as
         the case may be.

                  Opinion of Counsel: Means a written opinion of legal counsel
         who (a) in the case of counsel for the Company may be (i) the General
         Counsel of the Company, (ii) Cooley Godward LLP, (iii) Vedder, Price,
         Kaufman, Kammholz & Day, or (iv) such other counsel designated by the
         Company and reasonably acceptable to the Trustee and (b) in the case of
         counsel for any Owner Trustee or any Loan Trustee may be such counsel
         as may be designated by any of them whether or not such counsel is an
         employee of any of them, and who shall be reasonably acceptable to the
         Trustee.

                  Other Pass Through Trust Agreements: Means each of the two
         other America West Airlines 1998-1 Pass Through Trust Agreements
         relating to America West Airlines Pass Through Trust, Series 1998-1A-O
         and America West Airlines Pass Through Trust, Series 1998-1C-O, dated
         the date hereof.

                  Other Trustees: Means the trustees under the Other Pass
         Through Trust Agreements, and any successor or other trustee appointed
         as provided therein.

                  Other Trusts: Means the America West Airlines Pass Through
         Trust, Series 1998-1A-O and America West Airlines Pass Through Trust,
         Series 1998-1C-O, created on the date hereof.
<PAGE>   14
                                      -9-


                  Outstanding: When used with respect to Certificates, means, as
         of the date of determination, all Certificates theretofore
         authenticated and delivered under this Agreement, except:

                           (i) Certificates theretofore canceled by the
                  Registrar or delivered to the Trustee or the Registrar for
                  cancellation;

                           (ii) Certificates for which money in the full amount
                  required to make the final distribution with respect to such
                  Certificates pursuant to Section 11.01 hereof has been
                  theretofore deposited with the Trustee in trust for the
                  Holders of such Certificates as provided in Section 4.01
                  pending distribution of such money to such Certificateholders
                  pursuant to payment of such final distribution; and

                           (iii) Certificates in exchange for or in lieu of
                  which other Certificates have been authenticated and delivered
                  pursuant to this Agreement.

                  Owned Aircraft: Has the meaning specified in the second
         recital to this Agreement.

                  Owner Participant: With respect to any Equipment Note relating
         to a Leased Aircraft, means the "Owner Participant" as referred to in
         the Indenture pursuant to which such Equipment Note is issued and any
         permitted successor or assign of such Owner Participant; and Owner
         Participants at any time of determination means all of the Owner
         Participants thus referred to in the Indentures.

                  Owner Trustee: With respect to any Equipment Note relating to
         a Leased Aircraft, means the "Owner Trustee", as referred to in the
         Indenture pursuant to which such Equipment Note is issued, not in its
         individual capacity but solely as trustee; and Owner Trustees means all
         of the Owner Trustees party to any of the Indentures.

                  Participation Agreement: Means each Participation Agreement to
         be entered into by the Trustee pursuant to the Note Purchase Agreement,
         as the same may be amended, supplemented or otherwise modified in
         accordance with its terms.

                  Paying Agent: Means the paying agent maintained and appointed
         for the Certificates pursuant to Section 7.12.

                  Permitted Investments: Means obligations of the United States
         of America or agencies or instrumentalities thereof for the payment of
         which the full faith and credit of the United States of America is
         pledged, maturing in not more than 60 days after the date of
         acquisition thereof or such lesser time as is required for the
         distribution of any Special Payments on a Special Distribution Date.

                  Person: Means any person, including any individual,
         corporation, limited liability company, partnership, joint venture,
         association, joint-stock company, trust, trustee, unincorporated
         organization, or government or any agency or political subdivision
         thereof.
<PAGE>   15
                                      -10-


                  Pool Balance: Means, as of any date, (i) the original
         aggregate face amount of the Certificates less (ii) the aggregate
         amount of all payments made in respect of such Certificates other than
         payments made in respect of interest or premium thereon or
         reimbursement of any costs or expenses incurred in connection therewith
         less (iii) the aggregate amount of unused Deposits distributed as a
         Final Withdrawal other than payments in respect of interest or premium
         thereon. The Pool Balance as of any Distribution Date shall be computed
         after giving effect to the payment of principal, if any, on the
         Equipment Notes or other Trust Property held in such Trust and the
         distribution thereof to be made on such Distribution Date and the
         distribution of the Final Withdrawal to be made on such Distribution
         Date.

                  Pool Factor: Means, as of any date, the quotient (rounded to
         the seventh decimal place) computed by dividing (i) the Pool Balance as
         at such date by (ii) the original aggregate face amount of the
         Certificates. The Pool Factor as of any Distribution Date shall be
         computed after giving effect to the payment of principal, if any, on
         the Equipment Notes or other Trust Property and the distribution
         thereof to be made on such Distribution Date and the distribution of
         the Final Withdrawal to be made on such Distribution Date.

                  PTC Event of Default: Means any failure to pay within 10
         Business Days of the due date thereof: (i) the outstanding Pool Balance
         on the Final Legal Distribution Date or (ii) interest due on the
         Certificates on any Distribution Date (unless the Subordination Agent
         shall have made an Interest Drawing or Drawings (as defined in the
         Intercreditor Agreement), or a withdrawal or withdrawals pursuant to
         Section 3.6(f) of the Intercreditor Agreement, with respect thereto in
         an aggregate amount sufficient to pay such interest and shall have
         distributed such amount to the Trustee).

                  QIB: Means a qualified institutional buyer as defined in Rule
         144A.

                  Record Date: Means (i) for Scheduled Payments to be
         distributed on any Regular Distribution Date, other than the final
         distribution, the 15th day (whether or not a Business Day) preceding
         such Regular Distribution Date, and (ii) for Special Payments to be
         distributed on any Special Distribution Date, other than the final
         distribution, the 15th day (whether or not a Business Day) preceding
         such Special Distribution Date.

                  Register and Registrar: Mean the register maintained and the
         registrar appointed pursuant to Sections 3.04 and 7.12.

                  Registration Event: Means the declaration of the effectiveness
         by the SEC of the Exchange Offer Registration Statement or the Shelf
         Registration Statement.

                  Registration Rights Agreement: Means the Exchange and
         Registration Rights Agreement dated as of October 6, 1998, among the
         Initial Purchasers, the Trustee, the Other Trustees and the Company, as
         amended, supplemented or otherwise modified from time to time in
         accordance with its terms.

                  Regular Distribution Date: With respect to distributions of
         Scheduled Payments in respect of the Certificates, means each date
         designated as a Regular Distribution Date
<PAGE>   16
                                      -11-


         in the Certificates issued pursuant to this Agreement, until payment of
         all the Scheduled Payments to be made under the Equipment Notes held in
         the Trust have been made; provided, however, that, if any such day
         shall not be a Business Day, the related distribution shall be made on
         the next succeeding Business Day without additional interest.

                  Regulation S: Means Regulation S under the Securities Act or
         any successor regulation thereto.

                  Regulation S Definitive Certificates: Has the meaning
         specified in Section 3.01(e).

                  Regulation S Global Certificates: Has the meaning specified in
         Section 3.01(d).

                  Related Pass Through Trust Agreement: Means the Pass Through
         Trust Agreement relating to the America West Airlines Pass Through
         Trust, Series 1998-1B-S, dated the date hereof, between the Company and
         the institution acting as trustee thereunder, which agreement becomes
         effective upon the execution and delivery of the Assignment and
         Assumption Agreement pursuant to Section 11.01.

                  Related Trust: Means the America West Pass Through Trust,
         Series 1998-1B-S, formed under the Related Pass Through Trust
         Agreement.

                  Related Trustee: Means the trustee under the Related Pass
         Through Trust Agreement.

                  Responsible Officer: With respect to the Trustee, any Loan
         Trustee and any Owner Trustee, means any officer in the Corporate Trust
         Office of the Trustee, Loan Trustee or Owner Trustee or any other
         officer customarily performing functions similar to those performed by
         the persons who at the time shall be such officers, respectively, or to
         whom any corporate trust matter is referred because of his knowledge of
         and familiarity with a particular subject.

                  Restricted Definitive Certificates: Has the meaning specified
         in Section 3.01(e).

                  Restricted Global Certificate: Has the meaning specified in
         Section 3.01(c).

                  Restricted Legend: Has the meaning specified in Section 3.02.

                  Restricted Period: Has the meaning specified in Section
         3.01(d).

                  Rule 144A: Means Rule 144A under the Securities Act and any
         successor rule thereto.

                  Scheduled Payment: With respect to any Equipment Note, means
         (i) any payment of principal or interest on such Equipment Note (other
         than any such payment which is not in fact received by the
         Subordination Agent within five days of the date on which such payment
         is scheduled to be made) due from the obligor thereon or (ii) any
         payment
<PAGE>   17
                                      -12-


         of interest on the Certificates with funds drawn under any Liquidity
         Facility, which payment represents the installment of principal at the
         stated maturity of such installment of principal on such Equipment
         Note, the payment of regularly scheduled interest accrued on the unpaid
         principal amount of such Equipment Note, or both; provided that any
         payment of principal, premium, if any, or interest resulting from the
         redemption or purchase of any Equipment Note shall not constitute a
         Scheduled Payment.

                  SEC: Means the Securities and Exchange Commission, as from
         time to time constituted or created under the United States Securities
         Exchange Act of 1934, as amended, or, if at any time after the
         execution of this instrument such Commission is not existing and
         performing the duties now assigned to it under the Trust Indenture Act,
         then the body performing such duties on such date.

                  Securities Act: Means the United States Securities Act of
         1933, as amended from time to time, or any successor thereto.

                  Shelf Registration Statement: Means the shelf registration
         statement which may be required to be filed by the Company with the SEC
         pursuant to any Registration Rights Agreement, other than an Exchange
         Offer Registration Statement.

                  Special Distribution Date: Means each date on which a Special
         Payment is to be distributed as specified in this Agreement; provided,
         however, that, if any such day shall not be a Business Day, the related
         distribution shall be made on the next succeeding Business Day without
         additional interest.

                  Special Redemption Premium: Means the premium payable by the
         Company in respect of the Final Withdrawal pursuant to the Note
         Purchase Agreement.

                  Special Payment: Means any payment (other than a Scheduled
         Payment) in respect of, or any proceeds of, any Equipment Note or Trust
         Indenture Estate (as defined in each Indenture) or Special Redemption
         Premium.

                  Special Payments Account: Means the account or accounts
         created and maintained pursuant to Section 4.01(b).

                  Subordination Agent: Has the meaning specified in the
         Intercreditor Agreement.

                  Substitute Aircraft: Has the meaning specified in the Note
         Purchase Agreement.

                  Tax: Means all license, recording, documentary, registration
         and other similar fees and all taxes, levies, imposts, duties, charges,
         assessments or withholdings of any nature whatsoever imposed by any
         Taxing Authority, together with any penalties, additions to tax, fines
         or interest thereon or additions thereto.

                  Taxing Authority: Means any federal, state or local government
         or other taxing authority in the United States, any foreign government
         or any political subdivision or taxing authority thereof, any
         international taxing authority or any territory or possession of the
         United States or any taxing authority thereof.
<PAGE>   18
                                      -13-


                  TIN: Has the meaning specified in Section 7.16.

                  Transfer Date: Has the meaning specified in Section 11.01.

                  Triggering Event: Has the meaning assigned to such term in the
         Intercreditor Agreement.

                  Trust: Means the trust created by this Agreement, the estate
         of which consists of the Trust Property.

                  Trust Indenture Act: Means the United States Trust Indenture
         Act of 1939, as amended from time to time, or any successor thereto.

                  Trust Property: Means (i) the Equipment Notes held as the
         property of the Trust and, subject to the Intercreditor Agreement, all
         monies at any time paid thereon and all monies due and to become due
         thereunder, (ii) funds from time to time deposited in the Certificate
         Account and the Special Payments Account and, subject to the
         Intercreditor Agreement, any proceeds from the sale by the Trustee
         pursuant to Article VI hereof of any Equipment Note and (iii) all
         rights of the Trust and the Trustee, on behalf of the Trust, under the
         Intercreditor Agreement, the Escrow Agreement, the Note Purchase
         Agreement and the Liquidity Facilities, including, without limitation,
         all rights to receive certain payments thereunder, and all monies paid
         to the Trustee on behalf of the Trust pursuant to the Intercreditor
         Agreement or the Liquidity Facilities, provided, that rights with
         respect to the Deposits or under the Escrow Agreement, except for the
         right to direct withdrawals for the purchase of Equipment Notes to be
         held herein, will not constitute Trust Property.

                  Trustee: Means Wilmington Trust Company, or its successor in
         interest, and any successor or other trustee appointed as provided
         herein.

                  Trustee's Lien: Has the meaning specified in Section 7.17.

                  Unindemnified Tax: Means (i) any Tax imposed on the net
         income, net worth or capital, or any franchise Tax or similar doing
         business Tax, of the Pass Through Trustee (other than any such Tax
         imposed as a result of the Company's assumption of the Equipment Notes
         pursuant to the purchase of an aircraft on an EBO Date or a Material
         Adverse Tax Event), (ii) any withholding Tax imposed by the United
         States (including, without limitation, any withholding Tax imposed by
         the United States which is imposed or increased as a result of the Pass
         Through Trustee failing to deliver to the Company any certificate or
         document necessary to establish that payments under this Agreement are
         exempt from withholding Tax), and (iii) any Avoidable Tax.

                  Section 1.02. Compliance Certificates and Opinions. Upon any
application or request (except with respect to matters set forth in Article II)
by the Company, any Owner Trustee or any Loan Trustee to the Trustee to take any
action under any provision of this Agreement, the Company, such Owner Trustee or
such Loan Trustee, as the case may be, shall furnish to the Trustee (i) an
Officer's Certificate stating that, in the opinion of the signers, all
conditions precedent, if any, provided for in this Agreement relating to the
proposed action have
<PAGE>   19
                                      -14-


been complied with and (ii) an Opinion of Counsel stating that in the opinion of
such counsel all such conditions precedent, if any, have been complied with,
except that in the case of any such application or request as to which the
furnishing of such documents is specifically required by any provision of this
Agreement relating to such particular application or request, no additional
certificate or opinion need be furnished.

                  Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Agreement (other than a certificate
provided pursuant to Section 8.04(e)) shall include:

                  (1) a statement that each individual signing such certificate
         or opinion has read such covenant or condition and the definitions in
         this Agreement relating thereto;

                  (2) a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                  (3) a statement that, in the opinion of each such individual,
         he has made such examination or investigation as is necessary to enable
         him to express an informed opinion as to whether or not such covenant
         or condition has been complied with; and

                  (4) a statement as to whether, in the opinion of each such
         individual, such condition or covenant has been complied with.

                  Section 1.03. Form of Documents Delivered to Trustee. In any
case where several matters are required to be certified by, or covered by an
opinion of, any specified Person, it is not necessary that all such matters be
certified by, or covered by the opinion of, only one such Person, or that they
be so certified or covered by only one document, but one such Person may certify
or give an opinion with respect to some matters and one or more other such
Persons as to other matters and any such Person may certify or give an opinion
as to such matters in one or several documents.

                  Where any Person is required to make, give or execute two or
more applications, requests, consents, certificates, statements, opinions or
other instruments under this Agreement or, in respect of the Certificates, this
Agreement, they may, but need not, be consolidated and form one instrument.

                  Section 1.04. Directions of Certificateholders. (a) Any
direction, consent, request, demand, authorization, notice, waiver or other
action provided by this Agreement to be given or taken by Certificateholders (a
"Direction") may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Certificateholders in person or by an
agent or proxy duly appointed in writing; and, except as herein otherwise
expressly provided, such action shall become effective when such instrument or
instruments are delivered to the Trustee and, where it is hereby expressly
required pursuant to this Agreement, to the Company or any Loan Trustee. Proof
of execution of any such instrument or of a writing appointing any such agent or
proxy shall be sufficient for any purpose of this Agreement and conclusive in
favor of the Trustee, the Company and any Loan Trustee, if made in the manner
provided in this Section.
<PAGE>   20
                                      -15-


                  (b) The fact and date of the execution by any Person of any
such instrument or writing may be proved by the certificate of any notary public
or other officer of any jurisdiction authorized to take acknowledgments of deeds
or administer oaths that the Person executing such instrument acknowledged to
him the execution thereof, or by an affidavit of a witness to such execution
sworn to before any such notary or such other officer and where such execution
is by an officer of a corporation or association or a member of a partnership,
on behalf of such corporation, association or partnership, such certificate or
affidavit shall also constitute sufficient proof of his authority. The fact and
date of the execution of any such instrument or writing, or the authority of the
Person executing the same, may also be proved in any other reasonable manner
which the Trustee deems sufficient.

                  (c) In determining whether the Certificateholders of the
requisite Fractional Undivided Interests of Certificates Outstanding have given
any Direction under this Agreement, Certificates owned by the Company or any
Affiliate thereof shall be disregarded and deemed not to be Outstanding for
purposes of any such determination. In determining whether the Trustee shall be
protected in relying upon any such Direction, only Certificates which the
Trustee knows to be so owned shall be so disregarded. Notwithstanding the
foregoing, (i) if any such Person owns 100% of the Certificates Outstanding,
such Certificates shall not be so disregarded, and (ii) if any amount of
Certificates so owned by any such Person have been pledged in good faith, such
Certificates shall not be disregarded if the pledgee establishes to the
satisfaction of the Trustee the pledgee's right so to act with respect to such
Certificates and that the pledgee is not the Company or any Affiliate thereof.

                  (d) For all purposes of this Agreement, all Initial
Certificates and all Exchange Certificates shall vote and take all other actions
of Certificateholders together as one series of Certificates.

                  (e) The Company may at its option, by delivery of an Officer's
Certificate to the Trustee, set a record date to determine the
Certificateholders entitled to give any Direction. Notwithstanding Section
316(c) of the Trust Indenture Act, such record date shall be the record date
specified in such Officer's Certificate, which shall be a date not more than 30
days prior to the first solicitation of Certificateholders in connection
therewith. If such a record date is fixed, such Direction may be given before or
after such record date, but only the Certificateholders of record at the close
of business on such record date shall be deemed to be Certificateholders for the
purposes of determining whether Certificateholders of the requisite proportion
of Outstanding Certificates have authorized or agreed or consented to such
Direction, and for that purpose the Outstanding Certificates shall be computed
as of such record date; provided that no such Direction by the
Certificateholders on such record date shall be deemed effective unless it shall
become effective pursuant to the provisions of this Agreement not later than one
year after such record date.

                  (f) Any Direction by the Holder of any Certificate shall bind
the Holder of every Certificate issued upon the transfer thereof or in exchange
therefor or in lieu thereof, whether or not notation of such Direction is made
upon such Certificate.
<PAGE>   21
                                      -16-


                  (g) Except as otherwise provided in Section 1.04(c),
Certificates owned by or pledged to any Person shall have an equal and
proportionate benefit under the provisions of this Agreement, without
preference, priority, or distinction as among all of the Certificates.

                                   ARTICLE II

                       ORIGINAL ISSUANCE OF CERTIFICATES;
                         ACQUISITION OF EQUIPMENT NOTES

                  Section 2.01. Issuance of Certificates; Acquisition of
Equipment Notes. (a) The Trustee is hereby directed (i) to execute and deliver
the Intercreditor Agreement, the Registration Rights Agreement, the Escrow
Agreement and the Note Purchase Agreement on or prior to the Issuance Date, each
in the form delivered to the Trustee by the Company and (ii) subject to the
respective terms thereof, to perform its obligations thereunder. Upon request of
the Company and the satisfaction or waiver of the closing conditions specified
in the Certificate Purchase Agreement, the Trustee shall execute, deliver,
authenticate, issue and sell Certificates in authorized denominations equalling
in the aggregate the amount set forth, with respect to the Trust, in Schedule II
to the Certificate Purchase Agreement evidencing the entire ownership interest
in the Trust, which amount equals the maximum aggregate principal amount of
Equipment Notes which may be purchased by the Trustee pursuant to the Note
Purchase Agreement. Except as provided in Sections 3.04, 3.05, 3.06, 3.07 and
3.10 hereof, the Trustee shall not execute, authenticate or deliver Certificates
in excess of the aggregate amount specified in this paragraph.

                  (b) On or after the Issuance Date, the Company may deliver
from time to time to the Trustee a Delivery Notice relating to one or more
Equipment Notes. After receipt of a Delivery Notice and in any case no later
than one Business Day prior to a Delivery Date as to which such Delivery Notice
relates (the "Applicable Delivery Date") (or, if the Issuance Date is an
Applicable Delivery Date, on the Issuance Date), the Trustee shall (as and when
specified in the Delivery Notice) instruct the Escrow Agent to provide a Notice
of Purchase Withdrawal to the Depositary requesting (A) the withdrawal of one or
more Deposits on the Applicable Delivery Date in accordance with and to the
extent permitted by the terms of the Escrow Agreement and the Deposit Agreement
and (B) the payment of all, or a portion, of such Deposit or Deposits in an
amount equal in the aggregate to the purchase price of such Equipment Notes to
or on behalf of the Owner Trustee or the Company, as the case may be, issuing
such Equipment Notes, all as shall be described in the Delivery Notice; provided
that, if the Issuance Date is an Applicable Delivery Date, such purchase price
shall be paid from a portion of the proceeds of the sale of the Certificates.
The Trustee shall (as and when specified in such Delivery Notice), subject to
the conditions set forth in Section 2 of the Note Purchase Agreement, enter into
and perform its obligations under the Participation Agreement specified in such
Delivery Notice (the "Applicable Participation Agreement") and cause such
certificates, documents and legal opinions relating to the Trustee to be duly
delivered as required by the Applicable Participation Agreement. If at any time
prior to the Applicable Delivery Date, the Trustee receives a notice of
postponement pursuant to Section 2(e) or 2(f) of the Note Purchase Agreement,
then the Trustee shall give the Depositary (with a copy to the Escrow Agent) a
notice of cancellation of such Notice of Purchase Withdrawal relating to such
Deposit or
<PAGE>   22
                                      -17-


Deposits on such Applicable Delivery Date. Upon satisfaction of the conditions
specified in the Note Purchase Agreement and the Applicable Participation
Agreement, the Trustee shall purchase the applicable Equipment Notes with the
proceeds of the withdrawals of one or more Deposits made on the Applicable
Delivery Date in accordance with the terms of the Deposit Agreement and the
Escrow Agreement (or, if the Issuance Date is the Applicable Delivery Date with
respect to such Applicable Participation Agreement, from a portion of the
proceeds of the sale of the Certificates). The purchase price of such Equipment
Notes shall equal the principal amount of such Equipment Notes. Amounts
withdrawn from such Deposit or Deposits in excess of the purchase price of the
Equipment Notes or to the extent not applied on the Applicable Delivery Date to
the purchase price of the Equipment Notes, shall be re-deposited by the Trustee
with the Depositary on the Applicable Delivery Date in accordance with the terms
of the Deposit Agreement.

                  Section 2.02. Withdrawal of Deposits. If any Deposits remain
outstanding on the Business Day next succeeding the Cut-Off Date, (i) (A) the
Trustee shall give the Escrow Agent notice that the Trustee's obligation to
purchase Equipment Notes under the Note Purchase Agreement has terminated and
instruct the Escrow Agent to provide a notice of Final Withdrawal to the
Depositary substantially in the form of Exhibit B to the Deposit Agreement (the
"Final Withdrawal Notice") and (B) the Trustee will make a demand upon the
Company under the Note Purchase Agreement for an amount equal to the Special
Redemption Premium, if applicable, such payment to be made on the Final
Withdrawal Date.

                  Section 2.03. Acceptance by Trustee. The Trustee, upon the
execution and delivery of this Agreement, acknowledges its acceptance of all
right, title and interest in and to the Trust Property and declares that the
Trustee holds and will hold such right, title and interest for the benefit of
all then present and future Certificateholders, upon the trusts herein set
forth. Subject to Section 7.14, the Trustee shall take all actions reasonably
necessary to effect the registration of all such Equipment Notes in the name of
the Subordination Agent. By its payment for and acceptance of each Certificate
issued to it under this Agreement, each initial Certificateholder as grantor of
the Trust thereby joins in the creation and declaration of the Trust.

                  Section 2.04. Limitation of Powers. The Trust is constituted
solely for the purpose of making the investment in the Equipment Notes, and,
except as set forth herein, the Trustee shall not be authorized or empowered to
acquire any other investments or engage in any other activities and, in
particular, the Trustee shall not be authorized or empowered to do anything that
would cause such Trust to fail to qualify as a "grantor trust" for federal
income tax purposes (including as subject to this restriction, acquiring any
Aircraft (as defined in the respective Indentures) by bidding such Equipment
Notes or otherwise, or taking any action with respect to any such Aircraft once
acquired).

                                   ARTICLE III

                                THE CERTIFICATES

                  Section 3.01. Title, Form, Denomination and Execution of
Certificates. (a) The Initial Certificates shall be known as the "7.12% Initial
Pass Through Certificates, Series 1998-1B-O" and the Exchange Certificates shall
be known as the "7.12% Exchange Pass Through
<PAGE>   23
                                      -18-


Certificates, Series 1998-1B-O", in each case, of the Trust. Each Certificate
will represent a fractional undivided interest in the Trust and shall be
substantially in the form set forth as Exhibit A hereto, with such appropriate
insertions, omissions, substitutions and other variations as are required or
permitted by this Agreement and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as may be
required to comply with the rules of any securities exchange or as may,
consistently herewith, be determined by the Trustee or the officers executing
such Certificates, as evidenced by the Trustee's or officer's execution of the
Certificates (provided that such letters, numbers or other marks of
identification and such legends or endorsements are in a form acceptable to the
Company). At the Escrow Agent's request under the Escrow Agreement, the Trustee
shall affix the corresponding Escrow Receipt to each Certificate. In any event,
any transfer or exchange of any Certificate shall also effect a transfer or
exchange of the related Escrow Receipt. Prior to the Final Withdrawal Date, no
transfer or exchange of any Certificate shall be permitted unless the
Corresponding Escrow Receipt is attached thereto and also is so transferred or
exchanged. By acceptance of any Certificate to which an Escrow Receipt is
attached, each Holder of such a Certificate acknowledges and accepts the
restrictions on transfer of the Escrow Receipt set forth herein and in the
Escrow Agreement.

                  (b) The Initial Certificates shall be issued only in fully
registered form without coupons and only in denominations of $100,000 or
integral multiples of $1,000 in excess thereof, except that one Certificate may
be issued in a different denomination. The Exchange Certificates will be issued
in denominations of $1,000 or integral multiples thereof, except that one
Certificate may be issued in a different denomination. Each Certificate shall be
dated the date of its authentication. The aggregate Fractional Undivided
Interest of Certificates shall not at any time exceed $41,154,000.

                  (c) The Initial Certificates offered and sold in reliance on
Rule 144A shall be issued in the form of one or more Global Certificates
substantially in the form of Exhibit A hereto with such applicable legends as
are provided for in Section 3.02 (each a "Restricted Global Certificate") duly
executed and authenticated by the Trustee as hereinafter provided. Such
Restricted Global Certificates shall be in registered form and be registered in
the name of DTC and deposited with the Trustee, at its Corporate Trust Office,
as custodian for DTC. The aggregate principal amount of any Restricted Global
Certificate may from time to time be increased or decreased by adjustments made
on the records of the Trustee, as custodian for DTC for such Restricted Global
Certificate, as provided in Section 3.06 hereof, which adjustments shall be
conclusive as to the aggregate principal amount of any such Global Certificate.

                  (d) The Initial Certificates offered and sold outside the
United States in reliance on Regulation S shall be issued in the form of one or
more global Certificates substantially in the form of Exhibit A hereto (each a
"Regulation S Global Certificate") duly executed and authenticated by the
Trustee as hereinafter provided. Such Regulation S Global Certificates shall be
in registered form and be registered in the name of DTC and deposited with the
Trustee, at its Corporate Trust Office, as custodian for DTC, for credit
initially and during the Restricted Period (hereinafter defined) to the
respective accounts of beneficial owners of such Certificates (or to such other
accounts as they may direct) at Morgan Guaranty Trust Company of New York,
Brussels office, as operator of Euroclear or Cedel. As used herein, the term
"Restricted Period", with respect to the Regulation S Global Certificates
offered and sold in
<PAGE>   24
                                      -19-


reliance on Regulation S, means the period of 40 consecutive days beginning on
and including the later of (i) the day on which the Certificates are first
offered to persons other than distributors (as defined in Regulation S) in
reliance on Regulation S and (ii) the date of the closing of the offering under
the Certificate Purchase Agreement. The aggregate principal amount of any
Regulation S Global Certificate may from time to time be increased or decreased
by adjustments made on the records of the Trustee, as custodian for DTC for such
Global Certificate, as provided in Section 3.06 hereof, which adjustments shall
be conclusive as to the aggregate principal amount of any such Global
Certificate. The Restricted Global Certificate and Regulation S Global
Certificate are sometimes collectively referred to herein as the "Global
Certificates".

                  (e) Initial Certificates offered and sold to any Institutional
Accredited Investor which is not a QIB in a transaction exempt from registration
under the Securities Act (and other than as described in Section 3.01(d)) shall
be issued substantially in the form of Exhibit A hereto in definitive, fully
registered form without interest coupons with such applicable legends as are
provided for in Section 3.02 (the "Restricted Definitive Certificates") duly
executed and authenticated by the Trustee as hereinafter provided. Certificates
issued pursuant to Section 3.05(b) in exchange for interests in a Regulation S
Global Certificate shall be issued in definitive, fully registered form without
interest coupons (the "Regulation S Definitive Certificates"). The Restricted
Definitive Certificates and the Regulation S Definitive Certificates are
sometimes collectively referred to herein as the "Definitive Certificates".

                  (f) The Exchange Certificates shall be issued in the form of
one or more global Certificates substantially in the form of Exhibit A hereto
(each, a "Global Exchange Certificate"), except that (i) the Restricted Legend
(hereinafter defined) shall be omitted and (ii) such Exchange Certificates shall
contain such appropriate insertions, omissions, substitutions and other
variations from the form set forth in Exhibit A hereto relating to the nature of
the Exchange Certificates as the Responsible Officer of the Trustee executing
such Exchange Certificates on behalf of the Trust may determine, as evidenced by
such officer's execution on behalf of the Trust of such Exchange Certificates.
Such Global Exchange Certificates shall be in registered form and be registered
in the name of DTC and deposited with the Trustee, at its Corporate Trust
Office, as custodian for DTC. The aggregate principal amount of any Global
Exchange Certificate may from time to time be increased or decreased by
adjustments made on the records of the Trustee, as custodian for DTC for such
Global Exchange Certificate, which adjustments shall be conclusive as to the
aggregate principal amount of any such Global Exchange Certificate. Subject to
clause (i) and (ii) of the first sentence of this Section 3.01(f), the terms
hereof applicable to Restricted Global Certificates and/or Global Certificates
shall apply to the Global Exchange Certificates, mutatis mutandis.

                  (g) The Definitive Certificates shall be in registered form
and shall be typed, printed, lithographed or engraved or produced by any
combination of these methods or may be produced in any other manner, all as
determined by the officers executing such Certificates, as evidenced by their
execution of such Certificates.

                  Section 3.02. Restrictive Legends. All Initial Certificates
issued pursuant to this Agreement for resale pursuant to Rule 144A or offered
and sold to any Institutional Accredited Investor which is not a QIB (including
any Global Certificate issued upon registration of
<PAGE>   25
                                      -20-


transfer, in exchange for or in lieu of such Certificates) shall be "Restricted
Certificates" and shall bear a legend to the following effect (the "Restricted
Legend") unless the Company and the Trustee determine otherwise consistent with
applicable law:

                  THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE U.S.
         SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND
         ACCORDINGLY, MAY NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR TO,
         OR FOR THE ACCOUNT OR BENEFIT OF, ANY PERSONS EXCEPT AS SET FORTH IN
         THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF, THE HOLDER (1)
         REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED
         IN RULE 144A UNDER THE SECURITIES ACT), (B) IT IS AN INSTITUTIONAL
         "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(a)(1), (2), (3) OR (7) OF
         REGULATION D UNDER THE SECURITIES ACT) (AN "INSTITUTIONAL ACCREDITED
         INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THIS
         CERTIFICATE IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH REGULATION S
         UNDER THE SECURITIES ACT; (2) AGREES THAT IT WILL NOT WITHIN TWO YEARS
         AFTER THE LATER OF THE ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE
         LAST DATE ON WHICH THIS CERTIFICATE WAS HELD BY AMERICA WEST AIRLINES,
         INC., THE TRUSTEE OR ANY AFFILIATE OF ANY OF SUCH PERSONS RESELL OR
         OTHERWISE TRANSFER THIS CERTIFICATE EXCEPT (A) TO AMERICA WEST
         AIRLINES, INC., (B) TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE
         WITH RULE 144A UNDER THE SECURITIES ACT, (C) OUTSIDE THE UNITED STATES
         IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH RULE 904 UNDER THE
         SECURITIES ACT, (D) PURSUANT TO THE EXEMPTION FROM REGISTRATION
         PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE) OR (E)
         PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES
         ACT; AND (3) AGREES THAT IF IT SHOULD RESELL OR OTHERWISE TRANSFER THIS
         CERTIFICATE IT WILL DELIVER TO EACH PERSON TO WHOM THIS CERTIFICATE IS
         TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN
         CONNECTION WITH ANY TRANSFER OF THIS CERTIFICATE WITHIN TWO YEARS AFTER
         THE LATER OF THE ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE
         ON WHICH THIS CERTIFICATE WAS HELD BY AMERICA WEST AIRLINES, INC., THE
         TRUSTEE OR ANY AFFILIATE OF ANY OF SUCH PERSONS, THE HOLDER MUST CHECK
         THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING TO THE
         MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE. AS
         USED HEREIN, THE TERMS "OFFSHORE TRANSACTION", "UNITED STATES" AND
         "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE
         SECURITIES ACT. THE PASS THROUGH TRUST AGREEMENT CONTAINS A PROVISION
         REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS
         CERTIFICATE IN VIOLATION OF THE FOREGOING RESTRICTIONS.

                  Each Global Certificate shall bear the following legend on the
face thereof:
<PAGE>   26
                                      -21-


                  UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
         REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION
         ("DTC"), TO THE TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER,
         EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS
         CERTIFICATE IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER
         NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
         PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS
         REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE
         OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
         WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
         INTEREST HEREIN.

                  TRANSFERS OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO
         TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A
         SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS
         OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO TRANSFERS MADE IN
         ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN SECTIONS 3.05 AND 3.06 OF
         THE PASS THROUGH TRUST AGREEMENT REFERRED TO HEREIN.

                  Section 3.03. Authentication of Certificates. (a) On the
Issuance Date, the Trustee shall duly execute, authenticate and deliver
Certificates in authorized denominations equalling in the aggregate the amount
set forth, with respect to the Trust, in Schedule II to the Certificate Purchase
Agreement, evidencing the entire ownership of the Trust, which amount equals the
maximum aggregate principal amount of Equipment Notes which may be purchased by
the Trustee pursuant to the Note Purchase Agreement.

                  (b) No Certificate shall be entitled to any benefit under this
Agreement or be valid or obligatory for any purpose, unless there appears on
such Certificate a certificate of authentication substantially in the form
provided for herein executed by the Trustee by the manual signature of one of
its authorized signatories, and such certificate upon any Certificate shall be
conclusive evidence, and the only evidence, that such Certificate has been duly
authenticated and delivered hereunder.

                  (c) Certificates bearing the manual or facsimile signature of
an individual who was, at the time when such signature was affixed, authorized
to sign on behalf of the Trustee shall be valid and binding obligations of the
Trust notwithstanding that such individual has ceased to be so authorized prior
to the authentication and delivery of such Certificates or did not hold such
office on the date of such Certificates.

                  Section 3.04. Transfer and Exchange. The Trustee shall cause
to be kept at the office or agency to be maintained by it in accordance with the
provisions of Section 7.12 a register (the "Register") of the Certificates in
which, subject to such reasonable regulations as it may prescribe, the Trustee
shall provide for the registration of such Certificates and of transfers and
exchanges of such Certificates as herein provided. The Trustee shall initially
be the registrar (the "Registrar") for the purpose of registering such
Certificates and transfers and exchanges of 
<PAGE>   27
                                      -22-


such Certificates as herein provided. The Company, upon notice to the Trustee,
may change the Registrar at any time.

                  All Certificates issued upon any registration of transfer or
exchange of Certificates shall be valid obligations of the Trust, evidencing the
same interest therein, and entitled to the same benefits under this Trust
Agreement, as the Certificates surrendered upon such registration of transfer or
exchange.

                  A Certificateholder may transfer a Certificate, or request
that a Certificate be exchanged for Certificates in an aggregate Fractional
Undivided Interest equal to the Fractional Undivided Interest of such
Certificate surrendered for exchange of other authorized denominations, by
surrender of such Certificate to the Trustee with the form of transfer notice
thereon duly completed and executed, and otherwise complying with the terms of
this Agreement, including providing evidence of compliance with any restrictions
on transfer, in form satisfactory to the Trustee and the Registrar; provided
that no exchanges of Initial Certificates for Exchange Certificates shall occur
until an Exchange Offer Registration Statement shall have been declared
effective by the SEC (notice of which shall be provided to the Trustee by the
Company). No such transfer shall be effected until, and such transferee shall
succeed to the rights of a Certificateholder only upon, final acceptance and
registration of the transfer by the Registrar in the Register. Prior to the
registration of any transfer by a Certificateholder as provided herein, the
Trustee shall treat the person in whose name the Certificate is registered as
the owner thereof for all purposes, and the Trustee shall not be affected by
notice to the contrary. Furthermore, DTC shall, by acceptance of a Global
Certificate, agree that transfers of beneficial interests in such Global
Certificate may be effected only through a book-entry system maintained by DTC
(or its agent) and that ownership of a beneficial interest in the Certificate
shall be required to be reflected in a book-entry. When Certificates are
presented to the Registrar with a request to register the transfer thereof or to
exchange them for other authorized denominations of a Certificate in a
Fractional Undivided Interest equal to the aggregate Fractional Undivided
Interest of Certificates surrendered for exchange, the Registrar shall register
the transfer or make the exchange as requested if its requirements for such
transactions are met.

                  To permit registrations of transfers and exchanges in
accordance with the terms, conditions and restrictions hereof, the Trustee shall
execute and authenticate Certificates at the Registrar's request. No service
charge shall be made to a Certificateholder for any registration of transfer or
exchange of Certificates, but the Trustee shall require payment of a sum
sufficient to cover any tax or governmental charge that may be imposed in
connection with any transfer or exchange of Certificates. All Certificates
surrendered for registration of transfer or exchange shall be canceled and
subsequently destroyed by the Trustee.

                  Section 3.05. Book-Entry Provisions for Restricted Global
Certificates and Regulation S Global Certificates. (a) Members of, or
participants in, DTC ("Agent Members") shall have no rights under this Agreement
with respect to any Global Certificate held on their behalf by DTC, or the
Trustee as its custodian, and DTC may be treated by the Trustee and any agent of
the Trustee as the absolute owner of such Global Certificate for all purposes
whatsoever. Notwithstanding the foregoing, nothing herein shall prevent the
Trustee or any agent of the Trustee from giving effect to any written
certification, proxy or other authorization furnished by DTC or shall impair, as
between DTC and its Agent Members, the operation of customary
<PAGE>   28
                                      -23-


practices governing the exercise of the rights of a holder of any Certificate.
Upon the issuance of any Global Certificate, the Registrar or its duly appointed
agent shall record DTC as the registered holder of such Global Certificate.

                  (b) Transfers of any Global Certificate shall be limited to
transfers of such Restricted Global Certificate or Regulation S Global
Certificate in whole, but not in part, to DTC. Beneficial interests in the
Restricted Global Certificate and any Regulation S Global Certificate may be
transferred in accordance with the rules and procedures of DTC and the
provisions of Section 3.06. Beneficial interests in a Restricted Global
Certificate or a Regulation S Global Certificate shall be delivered to all
beneficial owners thereof in the form of Restricted Definitive Certificates or
Regulation S Definitive Certificates, as the case may be, if (i) DTC notifies
the Trustee that it is unwilling or unable to continue as depositary for such
Restricted Global Certificate or Regulation S Global Certificate, as the case
may be, and a successor depositary is not appointed by the Trustee within 90
days of such notice, and (ii) after the occurrence and during the continuance of
an Event of Default, owners of beneficial interests in a Global Certificate with
Fractional Undivided Interests aggregating not less than a majority in interest
in the Trust advise the Trustee, the Company and DTC through Agent Members in
writing that the continuation of a book-entry system through DTC or its
successor is no longer in their best interests.

                  (c) Any beneficial interest in one of the Global Certificates
that is transferred to a Person who takes delivery in the form of an interest in
another Global Certificate will, upon such transfer, cease to be an interest in
such Global Certificate and become an interest in the other Global Certificate
and, accordingly, will thereafter be subject to all transfer restrictions, if
any, and other procedures applicable to beneficial interests in such other
Global Certificate for as long as it remains such an interest.

                  (d) In connection with the transfer of an entire Restricted
Global Certificate or an entire Regulation S Global Certificate to the
beneficial owners thereof pursuant to paragraph (b) of this Section 3.05, such
Restricted Global Certificate or Regulation S Global Certificate, as the case
may be, shall be deemed to be surrendered to the Trustee for cancellation, and
the Trustee shall execute, authenticate and deliver, to each beneficial owner
identified by DTC in exchange for its beneficial interest in such Restricted
Global Certificate or Regulation S Global Certificate, as the case may be, an
equal aggregate principal amount of Restricted Definitive Certificates or
Regulation S Definitive Certificates, as the case may be, of authorized
denominations. None of the Company, the Registrar, the Paying Agent nor the
Trustee shall be liable for any delay in delivery of such instructions and may
conclusively rely on, and shall be protected in relying on, such registration
instructions. Upon the issuance of Definitive Certificates, the Trustee shall
recognize the Person in whose name the Definitive Certificates are registered in
the Register as Certificateholders hereunder. Neither the Company nor the
Trustee shall be liable if the Trustee or the Company is unable to locate a
qualified successor clearing agency.

                  (e) Any Definitive Certificate delivered in exchange for an
interest in the Restricted Global Certificate pursuant to paragraph (b) of this
Section 3.05 shall, except as otherwise provided by paragraph (e) of Section
3.06, bear the Restricted Legend.
<PAGE>   29
                                      -24-


                  (f) Prior to the expiration of the Restricted Period, any
Regulation S Definitive Certificate delivered in exchange for an interest in a
Regulation S Global Certificate pursuant to paragraph (b) of this Section shall
bear the Restricted Legend.

                  (g) The registered holder of any Restricted Global Certificate
or Regulation S Global Certificate may grant proxies and otherwise authorize any
Person, including Agent Members and Persons that may hold interests through
Agent Members, to take any action which a Holder is entitled to take under this
Agreement or the Certificates.

                  Section 3.06. Special Transfer Provisions. Unless and until
(i) an Initial Certificate is sold under an effective Shelf Registration
Statement, or (ii) an Initial Certificate is exchanged for an Exchange
Certificate pursuant to an effective Exchange Offer Registration Statement, in
each case pursuant to the terms of the Registration Rights Agreement, the
following provisions shall apply to such Initial Certificates:

                  (a) Transfers to Non-QIB Institutional Accredited Investors.
         The following provisions shall apply with respect to the registration
         of any proposed transfer of a Certificate to any Institutional
         Accredited Investor which is neither a QIB nor a Non-U.S. Person:

                           (i) The Registrar shall register the transfer of any
                  Certificate, whether or not bearing the Restricted Legend,
                  only if (x) the requested transfer is at least two years after
                  the later of the original issue date of the Certificates and
                  the last date on which such Certificate was held by the
                  Company, the Trustee or any affiliate of any of such Persons
                  or (y) the proposed transferor is an Initial Purchaser who is
                  transferring Certificates purchased under the Certificates
                  Purchase Agreement and the proposed transferee has delivered
                  to the Registrar a letter substantially in the form of Exhibit
                  C hereto and the aggregate principal amount of the
                  Certificates being transferred is at least $100,000. Except as
                  provided in the foregoing clause (y), the Registrar shall not
                  register the transfer of any Certificate to any Institutional
                  Accredited Investor which is neither a QIB nor a Non-U.S.
                  Person.

                           (ii) If the proposed transferor is an Agent Member
                  holding a beneficial interest in a Restricted Global
                  Certificate, upon receipt by the Registrar of (x) the
                  documents, if any, required by paragraph (i) and (y)
                  instructions given in accordance with DTC's and the
                  Registrar's procedures, the Registrar shall reflect on its
                  books and records the date of the transfer and a decrease in
                  the principal amount of such Restricted Global Certificate in
                  an amount equal to the principal amount of the beneficial
                  interest in such Restricted Global Certificate to be
                  transferred, and the Trustee shall execute, authenticate and
                  deliver to the transferor or at its direction, one or more
                  Restricted Definitive Certificates of like tenor and amount.

                  (b) Transfers to QIBs. The following provisions shall apply
         with respect to the registration of any proposed transfer of an Initial
         Certificate to a QIB (excluding Non-U.S. Persons):
<PAGE>   30
                                      -25-


                           (i) If the Certificate to be transferred consists of
                  Restricted Definitive Certificates, or of an interest in any
                  Regulation S Global Certificate during the Restricted Period,
                  the Registrar shall register the transfer if such transfer is
                  being made by a proposed transferor who has checked the box
                  provided for on the form of Initial Certificate stating, or
                  has otherwise advised the Trustee and the Registrar in
                  writing, that the sale has been made in compliance with the
                  provisions of Rule 144A to a transferee who has signed the
                  certification provided for on the form of Initial Certificate
                  stating, or has otherwise advised the Trustee and the
                  Registrar in writing, that it is purchasing the Initial
                  Certificate for its own account or an account with respect to
                  which it exercises sole investment discretion and that it, or
                  the Person on whose behalf it is acting with respect to any
                  such account, is a QIB within the meaning of Rule 144A, and is
                  aware that the sale to it is being made in reliance on Rule
                  144A and acknowledges that it has received such information
                  regarding the Trust and/or the Company as it has requested
                  pursuant to Rule 144A or has determined not to request such
                  information and that it is aware that the transferor is
                  relying upon its foregoing representations in order to claim
                  the exemption from registration provided by Rule 144A.

                           (ii) Upon receipt by the Registrar of the documents
                  required by clause (i) above and instructions given in
                  accordance with DTC's and the Registrar's procedures therefor,
                  the Registrar shall reflect on its books and records the date
                  of such transfer and an increase in the principal amount of a
                  Restricted Global Certificate in an amount equal to the
                  principal amount of the Restricted Definitive Certificates or
                  interests in such Regulation S Global Certificate, as the case
                  may be, being transferred, and the Trustee shall cancel such
                  Definitive Certificates or decrease the amount of such
                  Regulation S Global Certificate so transferred.

                  (c) Transfers of Interests in the Regulation S Global
         Certificate or Regulation S Definitive Certificates. After the
         expiration of the Restricted Period, the Registrar shall register any
         transfer of interests in any Regulation S Global Certificate or
         Regulation S Definitive Certificates without requiring any additional
         certification. Until the expiration of the Restricted Period, interests
         in the Regulation S Global Certificate may only be held through Agent
         Members acting for and on behalf of Euroclear and Cedel.

                  (d) Transfers to Non-U.S. Persons at Any Time. The following
         provisions shall apply with respect to any registration of any transfer
         of an Initial Certificate to a Non-U.S. Person:

                           (i) Prior to the expiration of the Restricted Period,
                  the Registrar shall register any proposed transfer of an
                  Initial Certificate to a Non-U.S. Person upon receipt of a
                  certificate substantially in the form set forth as Exhibit B
                  hereto from the proposed transferor.

                           (ii) After the expiration of the Restricted Period,
                  the Registrar shall register any proposed transfer to any
                  Non-U.S. Person if the Certificate to be transferred is a
                  Restricted Definitive Certificate or an interest in a
                  Restricted
<PAGE>   31
                                      -26-


                  Global Certificate, upon receipt of a certificate
                  substantially in the form of Exhibit B from the proposed
                  transferor. The Registrar shall promptly send a copy of such
                  certificate to the Company.

                           (iii) Upon receipt by the Registrar of (x) the
                  documents, if any, required by clause (ii) and (y)
                  instructions in accordance with DTC's and the Registrar's
                  procedures, the Registrar shall reflect on its books and
                  records the date of such transfer and a decrease in the
                  principal amount of such Restricted Global Certificate in an
                  amount equal to the principal amount of the beneficial
                  interest in such Restricted Global Certificate to be
                  transferred, and, upon receipt by the Registrar of
                  instructions given in accordance with DTC's and the
                  Registrar's procedures, the Registrar shall reflect on its
                  books and records the date and an increase in the principal
                  amount of the Regulation S Global Certificate in an amount
                  equal to the principal amount of the Restricted Definitive
                  Certificate or the Restricted Global Certificate, as the case
                  may be, to be transferred, and the Trustee shall cancel the
                  Definitive Certificate, if any, so transferred or decrease the
                  amount of such Restricted Global Certificate.

                  (e) Restricted Legend. Upon the transfer, exchange or
         replacement of Certificates not bearing the Restricted Legend, the
         Registrar shall deliver Certificates that do not bear the Restricted
         Legend. Upon the transfer, exchange or replacement of Certificates
         bearing the Restricted Legend, the Registrar shall deliver only
         Certificates that bear the Restricted Legend unless either (i) the
         circumstances contemplated by paragraph (d)(ii) of this Section 3.06
         exist or (ii) there is delivered to the Registrar an Opinion of Counsel
         to the effect that neither such legend nor the related restrictions on
         transfer are required in order to maintain compliance with the
         provisions of the Securities Act.

                  (f) General. By acceptance of any Certificate bearing the
         Restricted Legend, each Holder of such a Certificate acknowledges the
         restrictions on transfer of such Certificate set forth in this
         Agreement and agrees that it will transfer such Certificate only as
         provided in this Agreement. The Registrar shall not register a transfer
         of any Certificate unless such transfer complies with the restrictions
         on transfer, if any, of such Certificate set forth in this Agreement.
         In connection with any transfer of Certificates, each Certificateholder
         agrees by its acceptance of the Certificates to furnish the Registrar
         or the Trustee such certifications, legal opinions or other information
         as either of them may reasonably require to confirm that such transfer
         is being made pursuant to an exemption from, or a transaction not
         subject to, the registration requirements of the Securities Act and in
         accordance with the terms and provisions of this Article III; provided
         that the Registrar shall not be required to determine the sufficiency
         of any such certifications, legal opinions or other information.

                  Until such time as no Certificates remain Outstanding, the
Registrar shall retain copies of all letters, notices and other written
communications received pursuant to Section 3.05 or this Section 3.06. The
Trustee, if not the Registrar at such time, shall have the right to inspect and
make copies of all such letters, notices or other written communications at any
reasonable time upon the giving of reasonable written notice to the Registrar.
<PAGE>   32
                                      -27-


                  Section 3.07. Mutilated, Destroyed, Lost or Stolen
Certificates. If (a) any mutilated Certificate is surrendered to the Registrar
or the Registrar receives evidence to its satisfaction of the destruction, loss
or theft of any Certificate and (b) there is delivered to the Registrar and the
Trustee such security, indemnity or bond, as may be required by them to save
each of them harmless, then, in the absence of notice to the Registrar or the
Trustee that such destroyed, lost or stolen Certificate has been acquired by a
protected purchaser, and provided that the requirements of Section 8-405 of the
Uniform Commercial Code in effect in any applicable jurisdiction are met, the
Trustee shall execute, authenticate and deliver, in exchange for or in lieu of
any such mutilated, destroyed, lost or stolen Certificate, a new Certificate or
Certificates, in authorized denominations and of like Fractional Undivided
Interest and bearing a number not contemporaneously outstanding.

                  In connection with the issuance of any new Certificate under
this Section 3.07, the Trustee may require the payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in relation
thereto and any other expenses (including the fees and expenses of the Trustee
and the Registrar) connected therewith.

                  Any duplicate Certificate issued pursuant to this Section 3.07
shall constitute conclusive evidence of the appropriate Fractional Undivided
Interest in the Trust, as if originally issued, whether or not the lost, stolen
or destroyed Certificate shall be found at any time.

                  The provisions of this Section are exclusive and shall
preclude (to the extent lawful) all other rights and remedies with respect to
the replacement or payment of mutilated, destroyed, lost or stolen Certificates.

                  Section 3.08. Persons Deemed Owners. Prior to due presentment
of a Certificate for registration of transfer, the Trustee, the Registrar and
any Paying Agent may treat the Person in whose name any Certificate is
registered (as of the day of determination) as the owner of such Certificate for
the purpose of receiving distributions pursuant to Article IV and for all other
purposes whatsoever, and none of the Trustee, the Registrar or any Paying Agent
shall be affected by any notice to the contrary.

                  Section 3.09. Cancellation. All Certificates surrendered for
payment or transfer or exchange shall, if surrendered to the Trustee or any
agent of the Trustee other than the Registrar, be delivered to the Registrar for
cancellation and shall promptly be canceled by it. No Certificates shall be
authenticated in lieu of or in exchange for any Certificates canceled as
provided in this Section, except as expressly permitted by this Agreement. All
canceled Certificates held by the Registrar shall be destroyed and a
certification of their destruction delivered to the Trustee.

                  Section 3.10. Temporary Certificates. Until definitive
Certificates are ready for delivery, the Trustee shall authenticate temporary
Certificates. Temporary Certificates shall be substantially in the form of
definitive Certificates but may have insertions, substitutions, omissions and
other variations determined to be appropriate by the officers executing the
temporary Certificates, as evidenced by their execution of such temporary
Certificates. If temporary Certificates are issued, the Trustee will cause
definitive Certificates to be prepared without unreasonable delay. After the
preparation of definitive Certificates, the temporary
<PAGE>   33
                                      -28-


Certificates shall be exchangeable for definitive Certificates upon surrender of
the temporary Certificates at the office or agency of the Trustee designated for
such purpose pursuant to Section 7.12, without charge to the Certificateholder.
Upon surrender for cancellation of any one or more temporary Certificates, the
Trustee shall execute, authenticate and deliver in exchange therefor a like face
amount of definitive Certificates of authorized denominations. Until so
exchanged, the temporary Certificates shall be entitled to the same benefits
under this Agreement as definitive Certificates.

                  Section 3.11. Limitation of Liability for Payments. All
payments and distributions made to Certificateholders in respect of the
Certificates shall be made only from the Trust Property and only to the extent
that the Trustee shall have sufficient income or proceeds from the Trust
Property to make such payments in accordance with the terms of Article IV of
this Agreement. Each Certificateholder, by its acceptance of a Certificate,
agrees that it will look solely to the income and proceeds from the Trust
Property for any payment or distribution due to such Certificateholder pursuant
to the terms of this Agreement and that it will not have any recourse to the
Company, the Trustee, the Loan Trustees, the Liquidity Provider, the Owner
Trustees or the Owner Participants, except as otherwise expressly provided
herein or in the Intercreditor Agreement.

                  The Company is a party to this Agreement solely for purposes
of meeting the requirements of the Trust Indenture Act, and therefore shall not
have any right, obligation or liability hereunder (except as otherwise expressly
provided herein).

                  Section 3.12 ERISA Restrictive Legend. All Certificates issued
pursuant to this Agreement shall bear a legend to the following effect (the
"ERISA Legend") unless the Company and the Trustee determine otherwise
consistent with applicable law:

                  "BY ITS ACQUISITION HEREOF, THE HOLDER REPRESENTS THAT (A) NO
PLAN ASSETS HAVE BEEN USED TO PURCHASE THIS CERTIFICATE OR AN INTEREST HEREIN OR
(B) THE PURCHASE AND HOLDING OF THIS CERTIFICATE OR AN INTEREST HEREIN IS EXEMPT
FROM THE PROHIBITED TRANSACTION RESTRICTIONS OF ERISA AND THE CODE PURSUANT TO
ONE OR MORE PROHIBITED TRANSACTION STATUTORY OR ADMINISTRATIVE EXEMPTIONS. THE
PASS THROUGH TRUST AGREEMENT CONTAINS A PROVISION REQUIRING THE TRUSTEE TO
REFUSE TO REGISTER ANY TRANSFER OF THIS CERTIFICATE IN VIOLATION OF THE
FOREGOING RESTRICTIONS."

                  By acceptance of any Certificate bearing the ERISA Legend,
each Holder of such a Certificate acknowledges the restrictions on transfer of
such Certificate set forth in this Agreement and agrees that it will transfer
such Certificate only as provided in this Agreement. The Trustee shall not
register a transfer of any Certificate unless such transfer complies with the
restrictions on transfer, if any, of such Certificate set forth in such legend.
<PAGE>   34
                                      -29-


                                   ARTICLE IV

                          DISTRIBUTIONS; STATEMENTS TO
                               CERTIFICATEHOLDERS

                  Section 4.01. Certificate Account and Special Payments
Account. (a) The Trustee shall establish and maintain on behalf of the
Certificateholders a Certificate Account as one or more non-interest-bearing
accounts. The Trustee shall hold the Certificate Account in trust for the
benefit of the Certificateholders, and shall make or permit withdrawals
therefrom only as provided in this Agreement. On each day when a Scheduled
Payment is made to the Trustee under the Intercreditor Agreement, the Trustee
upon receipt thereof shall immediately deposit the aggregate amount of such
Scheduled Payment in the Certificate Account.

                  (b) The Trustee shall establish and maintain on behalf of the
Certificateholders a Special Payments Account as one or more accounts, which
shall be non-interest bearing except as provided in Section 4.04. The Trustee
shall hold the Special Payments Account in trust for the benefit of the
Certificateholders and shall make or permit withdrawals therefrom only as
provided in this Agreement. On each day when one or more Special Payments are
made to the Trustee under the Intercreditor Agreement and upon the payment of
the Special Redemption Premium to the Trustee under the Note Purchase Agreement,
the Trustee, upon receipt thereof, shall immediately deposit the aggregate
amount of such Special Payments in the Special Payments Account.

                  (c) The Trustee shall cause the Subordination Agent to present
to the related Loan Trustee of each Equipment Note such Equipment Note on the
date of its stated final maturity or, in the case of any Equipment Note which is
to be redeemed in whole pursuant to the related Indenture, on the applicable
redemption date under such Indenture.

                  Section 4.02. Distributions from Certificate Account and
Special Payments Account. (a) On each Regular Distribution Date or as soon
thereafter as the Trustee has confirmed receipt of the payment of all or any
part of the Scheduled Payments due on such date, the Trustee shall distribute
out of the Certificate Account the entire amount deposited therein pursuant to
Section 4.01(a). There shall be so distributed to each Certificateholder of
record on the Record Date with respect to such Regular Distribution Date (other
than as provided in Section 11.01 concerning the final distribution) by check
mailed to such Certificateholder, at the address appearing in the Register, such
Certificateholder's pro rata share (based on the Fractional Undivided Interest
in the Trust held by such Certificateholder) of the total amount in the
Certificate Account, except that, with respect to Certificates registered on the
Record Date in the name of DTC, such distribution shall be made by wire transfer
in immediately available funds to the account designated by DTC.

                  (b) On each Special Distribution Date with respect to any
Special Payment or as soon thereafter as the Trustee has confirmed receipt of
any Special Payments due on the Equipment Notes held in the related Trust or
realized upon the sale of such Equipment Notes or receipt of the Special
Redemption Premium, the Trustee shall distribute out of the Special Payments
Account the entire amount of such Special Payment deposited therein pursuant to
Section 4.01(b). There shall be so distributed to each Certificateholder of
record on the Record
<PAGE>   35
                                      -30-


Date with respect to such Special Distribution Date (other than as provided in
Section 11.01 concerning the final distribution) by check mailed to such
Certificateholder, at the address appearing in the Register, such
Certificateholder's pro rata share (based on the Fractional Undivided Interest
in the Trust held by such Certificateholder) of the total amount in the Special
Payments Account on account of such Special Payment, except that, with respect
to Certificates registered on the Record Date in the name of DTC, such
distribution shall be made by wire transfer in immediately available funds to
the account designated by DTC.

                  (c) The Trustee shall cause notice of each Special Payment to
be mailed to each Certificateholder at his address as it appears in the
Register. In the event of redemption or purchase of Equipment Notes held in the
Trust, such notice shall be mailed not less than 20 days prior to the Special
Distribution Date for the Special Payment resulting from such redemption or
purchase, which Special Distribution Date shall be the date of such redemption
or purchase. In the event of the payment of a Special Redemption Premium by the
Company to the Trustee under the Note Purchase Agreement, such notice shall be
mailed, together with the notice by the Escrow Paying Agent under Section 2.06
of the Escrow Agreement, not less than 20 days prior to the Special Distribution
Date for such amount, which Special Distribution Date shall be the Final
Withdrawal Date. In the case of any other Special Payments, such notice shall be
mailed as soon as practicable after the Trustee has confirmed that it has
received funds for such Special Payment, stating the Special Distribution Date
for such Special Payment which shall occur not less than 20 days after the date
of such notice and as soon as practicable thereafter. Notices mailed by the
Trustee shall set forth:

                  (i) the Special Distribution Date and the Record Date therefor
         (except as otherwise provided in Section 11.01),

                  (ii) the amount of the Special Payment for each $1,000 face
         amount Certificate and the amount thereof constituting principal,
         premium, if any, and interest,

                  (iii) the reason for the Special Payment, and

                  (iv) if the Special Distribution Date is the same date as a
         Regular Distribution Date, the total amount to be received on such date
         for each $1,000 face amount Certificate.

If the amount of (i) premium, if any, payable upon the redemption or purchase of
an Equipment Note or (ii) the Special Redemption Premium, if any, has not been
calculated at the time that the Trustee mails notice of a Special Payment, it
shall be sufficient if the notice sets forth the other amounts to be distributed
and states that any premium received will also be distributed.

                  If any redemption of the Equipment Notes held in the Trust is
canceled, the Trustee, as soon as possible after learning thereof, shall cause
notice thereof to be mailed to each Certificateholder at its address as it
appears on the Register.

                  Section 4.03. Statements to Certificateholders. (a) On each
Distribution Date, the Trustee will include with each distribution to
Certificateholders of a Scheduled Payment or Special Payment, as the case may
be, a statement setting forth the information provided below (in the case of a
Special Payment, including any Special Redemption Premium, reflecting in part
<PAGE>   36
                                      -31-


the information provided by the Escrow Paying Agent under the Escrow Agreement).
Such statement shall set forth (per $1,000 face amount Certificate as to (ii),
(iii), (iv) and (v) below) the following information:

                  (i) the aggregate amount of funds distributed on such
         Distribution Date hereunder and under the Escrow Agreement, indicating
         the amount allocable to each source;

                  (ii) the amount of such distribution hereunder allocable to
         principal and the amount allocable to premium (including the Special
         Redemption Premium), if any;

                  (iii) the amount of such distribution hereunder allocable to
         interest; and

                  (iv) the amount of such distribution under the Escrow
         Agreement allocable to interest;

                  (v) the amount of such distribution under the Escrow Agreement
         allocable to Deposits; and

                  (vi) the Pool Balance and the Pool Factor.

                  With respect to the Certificates registered in the name of
DTC, on the Record Date prior to each Distribution Date, the Trustee will
request from DTC a securities position listing setting forth the names of all
Agent Members reflected on DTC's books as holding interests in the Certificates
on such Record Date. On each Distribution Date, the Trustee will mail to each
such Agent Member the statement described above and will make available
additional copies as requested by such Agent Member for forwarding to holders of
interests in the Certificates.

                  (b) Within a reasonable period of time after the end of each
calendar year but not later than the latest date permitted by law, the Trustee
shall furnish to each Person who at any time during such calendar year was a
Certificateholder of record a statement containing the sum of the amounts
determined pursuant to clauses (a)(i), (a)(ii), (a)(iii), (a)(iv) and (a)(v)
above for such calendar year or, in the event such Person was a
Certificateholder of record during a portion of such calendar year, for such
portion of such year, and such other items as are readily available to the
Trustee and which a Certificateholder shall reasonably request as necessary for
the purpose of such Certificateholder's preparation of its federal income tax
returns. Such statement and such other items shall be prepared on the basis of
information supplied to the Trustee by the Agent Members and shall be delivered
by the Trustee to such Agent Members to be available for forwarding by such
Agent Members to the holders of interests in the Certificates in the manner
described in Section 4.03(a).

                  (c) Promptly following (i) the Delivery Period Termination
Date, if there has been any change in the information set forth in clauses (x),
(y) and (z) below from that set forth in page 69 of the Offering Circular, and
(ii) any early redemption or purchase of, or any default in the payment of
principal or interest in respect of, any of the Equipment Notes held in the
Trust, or any Final Withdrawal, the Trustee shall furnish to Certificateholders
of record on such date a statement setting forth (x) the expected Pool Balances
for each subsequent Regular Distribution Date following the Delivery Period
Termination Date, (y) the related Pool Factors
<PAGE>   37
                                      -32-


for such Regular Distribution Dates and (z) the expected principal distribution
schedule of the Equipment Notes, in the aggregate, held as Trust Property at the
date of such notice. With respect to the Certificates registered in the name of
DTC, on the Delivery Period Termination Date, the Trustee will request from DTC
a securities position listing setting forth the names of all Agent Members
reflected on DTC's books as holding interests in the Certificates on such date.
The Trustee will mail to each such Agent Member the statement described above
and will make available additional copies as requested by such Agent Member for
forwarding to holders of interests in the Certificates.

                  Section 4.04. Investment of Special Payment Moneys. Any money
received by the Trustee pursuant to Section 4.01(b) representing a Special
Payment which is not distributed on the date received shall, to the extent
practicable, be invested in Permitted Investments by the Trustee pending
distribution of such Special Payment pursuant to Section 4.02. Any investment
made pursuant to this Section 4.04 shall be in such Permitted Investments having
maturities not later than the date that such moneys are required to be used to
make the payment required under Section 4.02 on the applicable Special
Distribution Date and the Trustee shall hold any such Permitted Investments
until maturity. The Trustee shall have no liability with respect to any
investment made pursuant to this Section 4.04, other than by reason of the
willful misconduct or negligence of the Trustee. All income and earnings from
such investments shall be distributed on such Special Distribution Date as part
of such Special Payment.

                                    ARTICLE V

                                   THE COMPANY

                  Section 5.01. Maintenance of Corporate Existence. The Company,
at its own cost and expense, will do or cause to be done all things necessary to
preserve and keep in full force and effect its corporate existence, except as
permitted by Section 5.02.

                  Section 5.02. Consolidation, Merger, etc. The Company shall
not consolidate with or merge into any other corporation or convey, transfer or
lease substantially all of its assets as an entirety to any Person unless:

                  (a) the corporation formed by such consolidation or into which
         the Company is merged or the Person that acquires by conveyance,
         transfer or lease substantially all of the assets of the Company as an
         entirety shall be (i) organized and validly existing under the laws of
         the United States of America or any state thereof or the District of
         Columbia, (ii) a "citizen of the United States" as defined in 49 U.S.C.
         40102(a)(15), as amended, and (iii) a United States certificated air
         carrier, if and so long as such status is a condition of entitlement to
         the benefits of Section 1110 of the Bankruptcy Reform Act of 1978, as
         amended (11 U.S.C. Section 1110);

                  (b) the corporation formed by such consolidation or into which
         the Company is merged or the Person which acquires by conveyance,
         transfer or lease substantially all of the assets of the Company as an
         entirety shall execute and deliver to the Trustee a duly authorized,
         valid, binding and enforceable agreement in form and substance
         reasonably satisfactory to the Trustee containing an assumption by such
         successor corporation or
<PAGE>   38
                                      -33-


         Person of the due and punctual performance and observance of each
         covenant and condition of this Agreement, the Other Pass Through Trust
         Agreements and each Financing Document to be performed or observed by
         the Company; and

                  (c) the Company shall have delivered to the Trustee an
         Officer's Certificate of the Company reasonably satisfactory to the
         Trustee, stating that such consolidation, merger, conveyance, transfer
         or lease and the assumption agreement mentioned in clause (b) above
         comply with this Section 5.02 and that all conditions precedent herein
         provided for relating to such transaction have been complied with.

                  Upon any consolidation or merger, or any conveyance, transfer
or lease of substantially all of the assets of the Company as an entirety in
accordance with this Section 5.02, the successor corporation or Person formed by
such consolidation or into which the Company is merged or to which such
conveyance, transfer or lease is made shall succeed to, and be substituted for,
and may exercise every right and power of, the Company under this Agreement with
the same effect as if such successor corporation or Person had been named as the
Company herein. No such conveyance, transfer or lease of substantially all of
the assets of the Company as an entirety shall have the effect of releasing any
successor corporation or Person which shall have become such in the manner
prescribed in this Section 5.02 from its liability in respect of this Agreement
and any Financing Document to which it is a party.

                                   ARTICLE VI

                                     DEFAULT

                  Section 6.01. Events of Default. (a) Exercise of Remedies.
Upon the occurrence and during the continuation of any Indenture Default under
any Indenture, the Trustee may, to the extent it is the Controlling Party at
such time (as determined pursuant to the Intercreditor Agreement), direct the
exercise of remedies as provided in the Intercreditor Agreement.

                  (b) Purchase Rights of Certificateholders. (i) At any time
         after the occurrence and during the continuance of a Triggering Event,
         each Certificateholder shall have the right to purchase, for the
         purchase price set forth in the Class A Trust Agreement, all, but not
         less than all, of the Class A Certificates upon ten days' written
         notice to the Class A Trustee and each other Certificateholder,
         provided that (i) if prior to the end of such ten-day period any other
         Certificateholder notifies such purchasing Certificateholder that such
         other Certificateholder wants to participate in such purchase, then
         such other Certificateholder may join with the purchasing
         Certificateholder to purchase all, but not less than all, of the Class
         A Certificates pro rata based on the Fractional Undivided Interest in
         the Trust held by each such Certificateholder and (ii) if prior to the
         end of such ten-day period any other Certificateholder fails to notify
         the purchasing Certificateholder of such other Certificateholder's
         desire to participate in such a purchase, then such other
         Certificateholder shall lose its right to purchase the Class A
         Certificates pursuant to this Section 6.01(b); and

                  (ii) by acceptance of its Certificate, each Certificateholder
         agrees that at any time after the occurrence and during the
         continuation of a Triggering Event,
<PAGE>   39
                                      -34-


                           (A) each Class C Certificateholder shall have the
                  right (which shall not expire upon any purchase of the Class A
                  Certificates pursuant to clause (b)(i) above) to purchase all,
                  but not less than all, of the Class A Certificates and the
                  Certificates upon ten days' written notice to the Class A
                  Trustee, the Trustee and each other Class C Certificateholder,
                  provided that (1) if prior to the end of such ten-day period
                  any other Class C Certificateholder notifies such purchasing
                  Class C Certificateholder that such other Class C
                  Certificateholder wants to participate in such purchase, then
                  such other Class C Certificateholder may join with the
                  purchasing Class C Certificateholder to purchase all, but not
                  less than all, of the Class A Certificates and the
                  Certificates pro rata based on the Fractional Undivided
                  Interest in the Class C Trust, taken as a whole, held by each
                  such Class C Certificateholder and (2) if prior to the end of
                  such ten-day period any other Class C Certificateholder fails
                  to notify the purchasing Class C Certificateholder of such
                  other Class C Certificateholder's desire to participate in
                  such a purchase, then such other Class C Certificateholder
                  shall lose its right to purchase the Certificates pursuant to
                  this Section 6.01(b); and

                           (B) each Class D Certificateholder shall have the
                  right (which shall not expire upon any purchase of the Class A
                  Certificates pursuant to clause (b)(i) above or any purchase
                  of the Class A Certificates and the Certificates pursuant to
                  clause (b)(ii)(A) above) to purchase all, but not less than
                  all, of the Class A Certificates, the Certificates and the
                  Class C Certificates upon ten days' written notice to the
                  Class A Trustee, the Trustee, the Class C Trustee and each
                  other Class D Certificateholder, provided that (1) if prior to
                  the end of such ten-day period any other Class D
                  Certificateholder notifies such purchasing Class D
                  Certificateholder that such other Class D Certificateholder
                  wants to participate in such purchase, then such other Class D
                  Certificateholder may join with the purchasing Class D
                  Certificateholder to purchase all, but not less than all, of
                  the Class A Certificates, the Certificates and the Class C
                  Certificates pro rata based on the Fractional Undivided
                  Interest in the Class D Trust, taken as a whole, held by each
                  such Class D Certificateholder and (2) if prior to the end of
                  such ten day period any other Class D Certificateholder fails
                  to notify the purchasing Class D Certificateholder of such
                  other Class D Certificateholder's desire to participate in
                  such a purchase, then such other Class D Certificateholder
                  shall lose its right to purchase the Certificates pursuant to
                  this Section 6.01(b).

                  The purchase price with respect to the Certificates shall be
equal to the Pool Balance of the Certificates, together with accrued and unpaid
interest thereon to the date of such purchase, without premium, but including
any other amounts then due and payable to the Certificateholders under this
Agreement, the Intercreditor Agreement, the Escrow Agreement or any Financing
Document or on or in respect of the Certificates; provided, however, that (i) if
such purchase occurs after the record date specified in Section 2.03(b) of the
Escrow Agreement relating to the distribution of unused Deposits and accrued and
unpaid interest thereunder, such purchase price shall be reduced by the
aggregate amount of unused Deposits and interest to be distributed under the
Escrow Agreement (which deducted amounts shall remain distributable to, and may
be retained by, the Certificateholder as of such Record Date) and (ii) if such
purchase occurs after a Record Date, such purchase price shall be reduced by the
amount to be distributed
<PAGE>   40
                                      -35-


hereunder on the related Distribution Date (which deducted amounts shall remain
distributable to, and may be retained by, the Certificateholder as of such
Record Date); provided, further, that no such purchase of Certificates shall be
effective unless the purchaser(s) shall certify to the Trustee that
contemporaneously with such purchase, such purchaser(s) is purchasing, pursuant
to the terms of this Agreement and the Other Pass Through Trust Agreements, the
Class A Certificates, the Certificates and the Class C Certificates which are
senior to the securities held by such purchaser(s). Each payment of the purchase
price of the Certificates referred to in the first sentence hereof shall be made
to an account or accounts designated by the Trustee and each such purchase shall
be subject to the terms of this Section 6.01(b). Each Certificateholder agrees
by its acceptance of its Certificate that it will, subject to Section 3.04
hereof, upon payment from such Class C Certificateholder(s) or Class D
Certificateholder(s), as the case may be, of the purchase price set forth in the
first sentence of this paragraph, forthwith sell, assign, transfer and convey to
the purchaser(s) thereof (without recourse, representation or warranty of any
kind except for its own acts), all of the right, title, interest and obligation
of such Certificateholder in this Agreement, the Escrow Agreement, the Deposit
Agreement, the Intercreditor Agreement, the Liquidity Facility, the Financing
Documents and all Certificates and Escrow Receipts held by such
Certificateholder (excluding all right, title and interest under any of the
foregoing to the extent such right, title or interest is with respect to an
obligation not then due and payable as respects any action or inaction or state
of affairs occurring prior to such sale) and the purchaser shall assume all of
such Certificateholder's obligations under this Agreement, the Escrow Agreement,
the Deposit Agreement, the Intercreditor Agreement, the Liquidity Facility, the
Financing Documents and all such Certificates and Escrow Receipts. The
Certificates will be deemed to be purchased on the date payment of the purchase
price is made notwithstanding the failure of the Certificateholders to deliver
any Certificates (whether in the form of Definitive Certificates or beneficial
interests in Global Certificates) and, upon such a purchase, (i) the only rights
of the Certificateholders will be to deliver the Certificates to the
purchaser(s) and receive the purchase price for such Certificates and (ii) if
the purchaser(s) shall so request, such Certificateholder will comply with all
the provisions of Section 3.04 hereof to enable new Certificates to be issued to
the purchaser in such denominations as it shall request. All charges and
expenses in connection with the issuance of any such new Certificates shall be
borne by the purchaser thereof.

                  As used in this Section 6.01(b), the terms "Class A
Certificate", "Class A Certificateholder", "Class A Trust", "Class A Trust
Agreement", "Class A Trustee", "Class C Certificate", "Class C
Certificateholder", "Class C Trust", "Class C Trustee", "Class D Certificate",
and "Class D Trust", shall have the respective meanings assigned to such terms
in the Intercreditor Agreement.

                  Section 6.02. Incidents of Sale of Equipment Notes. Upon any
sale of all or any part of the Equipment Notes made either under the power of
sale given under this Agreement or otherwise for the enforcement of this
Agreement, the following shall be applicable:

                  (1) Certificateholders and Trustee May Purchase Equipment
         Notes. Any Certificateholder, the Trustee in its individual or any
         other capacity or any other Person may bid for and purchase any of the
         Equipment Notes, and upon compliance with the terms of sale, may hold,
         retain, possess and dispose of such Equipment Notes in their own
         absolute right without further accountability.
<PAGE>   41
                                      -36-


                  (2) Receipt of Trustee Shall Discharge Purchaser. The receipt
         of the Trustee making such sale shall be a sufficient discharge to any
         purchaser for his purchase money, and, after paying such purchase money
         and receiving such receipt, such purchaser or its personal
         representative or assigns shall not be obliged to see to the
         application of such purchase money, or be in any way answerable for any
         loss, misapplication or non-application thereof.

                  (3) Application of Moneys Received upon Sale. Any moneys
         collected by the Trustee upon any sale made either under the power of
         sale given by this Agreement or otherwise for the enforcement of this
         Agreement shall be applied as provided in Section 4.02.

                  Section 6.03. Judicial Proceedings Instituted by Trustee;
Trustee May Bring Suit. If there shall be a failure to make payment of the
principal of, premium, if any, or interest on any Equipment Note, or if there
shall be any failure to pay Rent (as defined in the relevant Lease) under any
Lease when due and payable, then the Trustee, in its own name and as trustee of
an express trust, as holder of such Equipment Notes, to the extent permitted by
and in accordance with the terms of the Intercreditor Agreement and the
Financing Documents (subject to the rights of the applicable Owner Trustee or
Owner Participant to cure any such failure to pay principal of, premium, if any,
or interest on any Equipment Note or to pay Rent under any Lease in accordance
with the applicable Indenture), shall be entitled and empowered to institute any
suits, actions or proceedings at law, in equity or otherwise, for the collection
of the sums so due and unpaid on such Equipment Notes or under such Lease and
may prosecute any such claim or proceeding to judgment or final decree with
respect to the whole amount of any such sums so due and unpaid.

                  Section 6.04 Control by Certificateholders. Subject to Section
6.03 and the Intercreditor Agreement, the Certificateholders holding
Certificates evidencing Fractional Undivided Interests aggregating not less than
a majority in interest in the Trust shall have the right to direct the time,
method and place of conducting any proceeding for any remedy available to the
Trustee with respect to the Trust or pursuant to the terms of the Intercreditor
Agreement, or exercising any trust or power conferred on the Trustee under this
Agreement or the Intercreditor Agreement, including any right of the Trustee as
Controlling Party under the Intercreditor Agreement or as holder of the
Equipment Notes, provided that:

                  (1) such Direction shall not be in conflict with any rule of
         law or with this Agreement and would not involve the Trustee in
         personal liability or expense,

                  (2) the Trustee shall not determine that the action so
         directed would be unjustly prejudicial to the Certificateholders not
         taking part in such Direction, and

                  (3) the Trustee may take any other action deemed proper by the
         Trustee which is not inconsistent with such Direction.

                  Section 6.05. Waiver of Past Defaults. Subject to the
Intercreditor Agreement, the Certificateholders holding Certificates evidencing
Fractional Undivided Interests aggregating not less than a majority in interest
in the Trust (i) may on behalf of all of the Certificateholders
<PAGE>   42
                                      -37-


waive any past Event of Default hereunder and its consequences or (ii) if the
Trustee is the Controlling Party, may direct the Trustee to instruct the
applicable Loan Trustee to waive any past Indenture Default under any Indenture
and its consequences, and thereby annul any Direction given by such
Certificateholders or the Trustee to such Loan Trustee with respect thereto,
except a default:

                  (1) in the deposit of any Scheduled Payment or Special Payment
         under Section 4.01 or in the distribution of any payment under Section
         4.02 on the Certificates, or

                  (2) in the payment of the principal of (premium, if any) or
         interest on the Equipment Notes, or

                  (3) in respect of a covenant or provision hereof which under
         Article IX cannot be modified or amended without the consent of each
         Certificateholder holding an Outstanding Certificate affected thereby.

                  Upon any such waiver, such default shall cease to exist with
respect to the Certificates and any Event of Default arising therefrom shall be
deemed to have been cured for every purpose and any direction given by the
Trustee on behalf of the Certificateholders to the relevant Loan Trustee shall
be annulled with respect thereto; but no such waiver shall extend to any
subsequent or other default or Event of Default or impair any right consequent
thereon. Upon any such waiver, the Trustee shall vote the Equipment Notes issued
under the relevant Indenture to waive the corresponding Indenture Default.

                  Section 6.06. Right of Certificateholders to Receive Payments
Not to Be Impaired. Anything in this Agreement to the contrary notwithstanding,
including, without limitation, Section 6.07 hereof, but subject to the
Intercreditor Agreement, the right of any Certificateholder to receive
distributions of payments required pursuant to Section 4.02 hereof on the
Certificates when due, or to institute suit for the enforcement of any such
payment on or after the applicable Regular Distribution Date or Special
Distribution Date, shall not be impaired or affected without the consent of such
Certificateholder.

                  Section 6.07. Certificateholders May Not Bring Suit Except
Under Certain Conditions. A Certificateholder shall not have the right to
institute any suit, action or proceeding at law or in equity or otherwise with
respect to this Agreement, for the appointment of a receiver or for the
enforcement of any other remedy under this Agreement, unless:

                  (1) such Certificateholder previously shall have given written
         notice to the Trustee of a continuing Event of Default;

                  (2) Certificateholders holding Certificates evidencing
         Fractional Undivided Interests aggregating not less than 25% of the
         Trust shall have requested the Trustee in writing to institute such
         action, suit or proceeding and shall have offered to the Trustee
         indemnity as provided in Section 7.03(e);

                  (3) the Trustee shall have refused or neglected to institute
         such an action, suit or proceeding for 60 days after receipt of such
         notice, request and offer of indemnity; and
<PAGE>   43
                                      -38-


                  (4) no direction inconsistent with such written request shall
         have been given to the Trustee during such 60-day period by
         Certificateholders holding Certificates evidencing Fractional Undivided
         Interests aggregating not less than a majority in interest in the
         Trust.

                  It is understood and intended that no one or more of the
Certificateholders shall have any right in any manner whatsoever hereunder or
under the Certificates to (i) surrender, impair, waive, affect, disturb or
prejudice any property in the Trust Property or the lien of any Indenture on any
property subject thereto, or the rights of the Certificateholders or the holders
of the Equipment Notes, (ii) obtain or seek to obtain priority over or
preference with respect to any other such Certificateholder or (iii) enforce any
right under this Agreement, except in the manner herein provided and for the
equal, ratable and common benefit of all the Certificateholders subject to the
provisions of this Agreement.

                  Section 6.08. Remedies Cumulative. Every remedy given
hereunder to the Trustee or to any of the Certificateholders shall not be
exclusive of any other remedy or remedies, and every such remedy shall be
cumulative and in addition to every other remedy given hereunder or now or
hereafter given by statute, law, equity or otherwise.

                                   ARTICLE VII

                                   THE TRUSTEE

                  Section 7.01. Certain Duties and Responsibilities. (a) Except
during the continuance of an Event of Default, the Trustee undertakes to perform
such duties as are specifically set forth in this Agreement, and no implied
covenants or obligations shall be read into this Agreement against the Trustee.

                  (b) In case an Event of Default has occurred and is
continuing, the Trustee shall exercise such of the rights and powers vested in
it by this Agreement, and use the same degree of care and skill in their
exercise, as a prudent man would exercise or use under the circumstances in the
conduct of its own affairs.

                  (c) No provision of this Agreement shall be construed to
relieve the Trustee from liability for its own negligent action, its own
negligent failure to act, or its own willful misconduct, except that

                  (1) this SubSection shall not be construed to limit the effect
         of SubSection (a) of this Section; and

                  (2) the Trustee shall not be liable for any error of judgment
         made in good faith by a Responsible Officer of the Trustee, unless it
         shall be proved that the Trustee was negligent in ascertaining the
         pertinent facts.

                  (d) Whether or not herein expressly so provided, every
provision of this Trust Agreement relating to the conduct or affecting the
liability of or affording protection to the Trustee shall be subject to the
provisions of this Section.
<PAGE>   44
                                      -39-


                  Section 7.02. Notice of Defaults. As promptly as practicable
after, and in any event within 90 days after, the occurrence of any default (as
such term is defined below) hereunder, the Trustee shall transmit by mail to the
Company, the Owner Trustees, the Owner Participants, the Loan Trustees and the
Certificateholders in accordance with Section 313(c) of the Trust Indenture Act,
notice of such default hereunder known to the Trustee, unless such default shall
have been cured or waived; provided, however, that, except in the case of a
default on the payment of the principal, premium, if any, or interest on any
Equipment Note held in the Trust, the Trustee shall be protected in withholding
such notice if and so long as the board of directors, the executive committee or
a trust committee of directors and/or Responsible Officers of the Trustee in
good faith determine that the withholding of such notice is in the interests of
the Certificateholders. For the purpose of this Section, the term "default"
means any event that is, or after notice or lapse of time or both would become,
an Event of Default.

                  Section 7.03. Certain Rights of Trustee. Subject to the
provisions of Section 315 of the Trust Indenture Act:

                  (a) the Trustee may rely and shall be protected in acting or
         refraining from acting in reliance upon any resolution, certificate,
         statement, instrument, opinion, report, notice, request, direction,
         consent, order, bond, debenture or other paper or document believed by
         it to be genuine and to have been signed or presented by the proper
         party or parties;

                  (b) any request or direction of the Company mentioned herein
         shall be sufficiently evidenced by a written description of the subject
         matter thereof accompanied by an Officer's Certificate and an Opinion
         of Counsel as provided in Section 1.02 of this Agreement;

                  (c) whenever in the administration of this Agreement the
         Trustee shall deem it desirable that a matter be proved or established
         prior to taking, suffering or omitting any action hereunder, the
         Trustee (unless other evidence be herein specifically prescribed) may,
         in the absence of bad faith on its part, rely upon an Officer's
         Certificate of the Company, any Owner Trustee or any Loan Trustee;

                  (d) the Trustee may consult with counsel and the advice of
         such counsel or any Opinion of Counsel shall be full and complete
         authorization and protection in respect of any action taken, suffered
         or omitted by it hereunder in good faith and in reliance thereon;

                  (e) the Trustee shall be under no obligation to exercise any
         of the rights or powers vested in it by this Agreement at the Direction
         of any of the Certificateholders pursuant to this Agreement, unless
         such Certificateholders shall have offered to the Trustee reasonable
         security or indemnity against the cost, expenses and liabilities which
         might be incurred by it in compliance with such Direction;

                  (f) the Trustee shall not be bound to make any investigation
         into the facts or matters stated in any resolution, certificate,
         statement, instrument, opinion, report, notice, request, direction,
         consent, order, bond, debenture or other paper or document;
<PAGE>   45
                                      -40-


                  (g) the Trustee may execute any of the trusts or powers under
         this Agreement or perform any duties under this Agreement either
         directly or by or through agents or attorneys, and the Trustee shall
         not be responsible for any misconduct or negligence on the part of any
         agent or attorney appointed with due care by it under this Agreement;

                  (h) the Trustee shall not be liable with respect to any action
         taken or omitted to be taken by it in good faith in accordance with the
         Direction of the Certificateholders holding Certificates evidencing
         Fractional Undivided Interests aggregating not less than a majority in
         interest in the Trust relating to the time, method and place of
         conducting any proceeding for any remedy available to the Trustee, or
         exercising any trust or power conferred upon the Trustee, under this
         Agreement; and

                  (i) the Trustee shall not be required to expend or risk its
         own funds in the performance of any of its duties under this Agreement,
         or in the exercise of any of its rights or powers, if it shall have
         reasonable grounds for believing that repayment of such funds or
         adequate indemnity against such risk is not reasonably assured to it.

                  Section 7.04. Not Responsible for Recitals or Issuance of
Certificates. The recitals contained herein and in the Certificates, except the
certificates of authentication, shall not be taken as the statements of the
Trustee, and the Trustee assumes no responsibility for their correctness.
Subject to Section 7.15, the Trustee makes no representations as to the validity
or sufficiency of this Agreement, any Equipment Notes, the Intercreditor
Agreement, the Deposit Agreement, the Escrow Agreement, the Certificates or any
other Financing Document, except that the Trustee hereby represents and warrants
that this Agreement has been, and the Intercreditor Agreement, the Registration
Rights Agreement, the Note Purchase Agreement, the Escrow Agreement and each
Certificate will be, executed, authenticated and delivered by one of its
officers who is duly authorized to execute, authenticate and deliver such
document on its behalf.

                  Section 7.05. May Hold Certificates. The Trustee, any Paying
Agent, Registrar or any of their Affiliates or any other agent in their
respective individual or any other capacity may become the owner or pledgee of
Certificates and, subject to Sections 310(b) and 311 of the Trust Indenture Act,
if applicable, may otherwise deal with the Company, the Owner Trustees or the
Loan Trustees with the same rights it would have if it were not Trustee, Paying
Agent, Registrar or such other agent.

                  Section 7.06. Money Held in Trust. Money held by the Trustee
or the Paying Agent in trust hereunder need not be segregated from other funds
except to the extent required herein or by law and neither the Trustee nor the
Paying Agent shall have any liability for interest upon any such moneys except
as provided for herein.

                  Section 7.07. Compensation and Reimbursement. The Company
agrees:

                  (1) to pay, or cause to be paid, to the Trustee from time to
         time reasonable compensation for all services rendered by it hereunder
         as set forth in a written fee letter dated the date hereof between the
         Company and the Trustee, which letter is incorporated
<PAGE>   46
                                      -41-


         herein by reference (which compensation shall not be limited by any
         provision of law in regard to the compensation of a trustee of an
         express trust);

                  (2) except as otherwise expressly provided herein, to
         reimburse, or cause to be reimbursed, the Trustee upon its request for
         all reasonable out-of-pocket expenses, disbursements and advances
         incurred or made by the Trustee in accordance with any provision of
         this Agreement (including the reasonable compensation and the expenses
         and disbursements of its agents and counsel), except any such expense,
         disbursement or advance as may be attributable to its undertaking its
         normal administrative functions, or its negligence, willful misconduct
         or bad faith or as may be incurred due to the Trustee's breach of its
         representations and warranties set forth in Section 7.15; and

                  (3) to indemnify, or cause to be indemnified, the Trustee for,
         and to hold it harmless against, any loss, liability, expense or Tax
         (other than for or with respect to any Unindemnified Tax) incurred
         without negligence, willful misconduct or bad faith, on its part,
         arising out of or in connection with the acceptance or administration
         of this Trust, including the costs and expenses of defending itself
         against any claim or liability in connection with the exercise or
         performance of any of its powers or duties hereunder, except for any
         such loss, liability or expense incurred by reason of the Trustee's
         breach of its covenants hereunder or under any Financing Document to
         which it is a party or its representations and warranties set forth in
         Section 7.15 or in any other Financing Document, the authorization or
         giving or withholding of any future amendments, supplements, waivers or
         consents with respect hereto or any of the Financing Documents, which
         amendments, supplements, waivers or consents are not required pursuant
         to the terms of the Financing Documents and not requested by the
         Company, any loss of tax benefits, any Unindemnified Tax, or increase
         in tax liability under any tax law whether or not the Company is
         required to indemnify thereof or pursuant to this Agreement or any
         costs associated with overhead or normal administration hereunder or
         any voluntary resignation pursuant to Section 7.09.

                  With respect to paragraph (3) above, the Trustee shall notify
the Company promptly of any claim for which it may seek indemnity and the
Company shall make payment on any such claim within 30 days of written demand
thereof (delivered together with supporting documentation). The Company shall
defend the claim and the Trustee shall cooperate in the defense. The Trustee may
have separate counsel with the consent of the Company and the Company will pay
the reasonable fees and expenses of such counsel. The Company need not pay for
any settlement made, in settlement or otherwise, without its consent.

                  With respect to any Tax other than an Unindemnified Tax, the
Trustee shall be entitled to reimbursement from, and shall have a lien prior to
the Certificates upon, the Trust Property for any such Tax incurred without
negligence, bad faith or willful misconduct, on its part, arising out of or in
connection with the acceptance or administration of such Trust (other than any
Tax attributable to the Trustee's compensation for serving as such), including
any costs and expenses incurred in contesting the imposition of any such Tax. If
the Trustee reimburses itself from the Trust Property of such Trust for any such
Tax, it will mail a brief report within 30 days setting forth the circumstances
thereof to all Certificateholders as their names and addresses appear in the
Register.
<PAGE>   47
                                      -42-


                  Section 7.08. Corporate Trustee Required; Eligibility. There
shall at all times be a Trustee hereunder which shall be eligible to act as a
trustee under Section 310(a) of the Trust Indenture Act and shall have a
combined capital and surplus of at least $75,000,000 (or a combined capital and
surplus in excess of $5,000,000 and the obligations of which, whether now in
existence or hereafter incurred, are fully and unconditionally guaranteed by a
corporation organized and doing business under the laws of the United States,
any state or territory thereof or of the District of Columbia and having a
combined capital and surplus of at least $75,000,000). If such corporation
publishes reports of conditions at least annually, pursuant to law or to the
requirements of federal, state, territorial or District of Columbia supervising
or examining authority, then for the purposes of this Section 7.08, the combined
capital and surplus of such corporation shall be deemed to be its combined
capital and surplus as set forth in its most recent report of conditions so
published.

                  In case at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section 7.08 to act as Trustee, the
Trustee shall resign immediately as Trustee in the manner and with the effect
specified in Section 7.09.

                  Section 7.09 Resignation and Removal; Appointment of
Successor. (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 7.10.

                  (b) The Trustee may resign at any time as trustee by giving
prior written notice thereof to the Company, the Authorized Agents, the Owner
Trustees and the Loan Trustees. If an instrument of acceptance by a successor
Trustee shall not have been delivered to the Company, the Authorized Agents, the
Owner Trustees, the Loan Trustees and the Trustee within 30 days after the
giving of such notice of resignation, the resigning Trustee may petition any
court of competent jurisdiction for the appointment of a successor Trustee.

                  (c) The Trustee may be removed at any time by Direction of the
Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in the Trust
delivered to the Trustee and to the Company, the Owner Trustees and the Loan
Trustees.

                  (d) If at any time:

                  (1) the Trustee shall fail to comply with Section 310 of the
         Trust Indenture Act, if applicable, after written request therefor by
         the Company or by any Certificateholder who has been a bona fide
         Certificateholder for at least six months; or

                  (2) the Trustee shall cease to be eligible under Section 7.08
         and shall fail to resign after written request therefor by the Company
         or by any such Certificateholder; or

                  (3) the Trustee shall become incapable of acting or shall be
         adjudged a bankrupt or insolvent or a receiver of the Trustee or of its
         property shall be appointed or any public officer shall take charge or
         control of the Trustee or of its property or affairs for the purpose of
         rehabilitation, conservation or liquidation;
<PAGE>   48
                                      -43-


then, in any case, (i) the Company may remove the Trustee or (ii) any
Certificateholder who has been a bona fide Certificateholder for at least six
months may, on behalf of itself and all others similarly situated, petition any
court of competent jurisdiction for the removal of the Trustee and the
appointment of a successor Trustee.

                  (e) If a Responsible Officer of the Trustee shall obtain
actual knowledge of an Avoidable Tax which has been or is likely to be asserted,
the Trustee shall promptly notify the Company and shall, within 30 days of such
notification, resign hereunder unless within such 30-day period the Trustee
shall have received notice that the Company has agreed to pay such tax. The
Company shall promptly appoint a successor Trustee in a jurisdiction where there
are no Avoidable Taxes.

                  (f) If the Trustee shall resign, be removed or become
incapable of acting or if a vacancy shall occur in the office of the Trustee for
any cause, the Company shall promptly appoint a successor Trustee. If, within
one year after such resignation, removal or incapability, or other occurrence of
such vacancy, a successor Trustee shall be appointed by Direction of the
Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in the Trust
delivered to the Company, the Owner Trustees, the Loan Trustees and the retiring
Trustee, and the Company approves such appointment, which approval shall not be
unreasonably withheld, then the successor Trustee so appointed shall, forthwith
upon its acceptance of such appointment, become the successor Trustee and
supersede the successor Trustee appointed as provided above. If no successor
Trustee shall have been so appointed as provided above and accepted appointment
in the manner hereinafter provided, any Certificateholder who has been a bona
fide Certificateholder for at least six months may, on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
appointment of a successor Trustee.

                  (g) The successor Trustee shall give notice of the resignation
and removal of the Trustee and appointment of the successor Trustee by mailing
written notice of such event by first-class mail, postage prepaid, to the
Certificateholders as their names and addresses appear in the Register. Each
notice shall include the name of such successor Trustee and the address of its
Corporate Trust Office.

                  Section 7.10. Acceptance of Appointment by Successor. Every
successor Trustee appointed hereunder shall execute and deliver to the Company,
the Authorized Agents, the Owner Trustees and the Loan Trustees and to the
retiring Trustee an instrument accepting such appointment, and thereupon the
resignation or removal of the retiring Trustee shall become effective and such
successor Trustee, without any further act, deed or conveyance, shall become
vested with all the rights, powers, trusts and duties of the retiring Trustee;
but, on request of the Company or the successor Trustee, such retiring Trustee
shall execute and deliver an instrument transferring to such successor Trustee
all such rights, powers and trusts of the retiring Trustee and shall duly
assign, transfer and deliver to such successor Trustee all Trust Property held
by such retiring Trustee hereunder, subject nevertheless to its lien, if any,
provided for in Section 7.07. Upon request of any such successor Trustee, the
Company, the retiring Trustee and such successor Trustee shall execute and
deliver any and all instruments containing such provisions as shall be necessary
or desirable to transfer and confirm to, and for more fully and certainly
vesting in, such successor Trustee all such rights, powers and trusts.
<PAGE>   49
                                      -44-


                  No institution shall accept its appointment as a Trustee
hereunder unless at the time of such acceptance such institution shall be
qualified and eligible under this Article VII.

                  Section 7.11. Merger, Conversion, Consolidation or Succession
to Business. Any corporation into which the Trustee may be merged or converted
or with which it may be consolidated, or any corporation resulting from any
merger, conversion or consolidation to which the Trustee shall be a party, or
any corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article VII, without the execution or filing of any paper or any further act on
the part of any of the parties hereto. In case any Certificates shall have been
executed or authenticated, but not delivered, by the Trustee then in office, any
successor by merger, conversion or consolidation to such authenticating Trustee
may adopt such execution or authentication and deliver the Certificates so
executed or authenticated with the same effect as if such successor Trustee had
itself executed or authenticated such Certificates.

                  Section 7.12. Maintenance of Agencies. (a) There shall at all
times be maintained an office or agency in the location set forth in Section
12.03 where Certificates may be presented or surrendered for registration of
transfer or for exchange, and for payment thereof and where notices and demands
to or upon the Trustee in respect of such certificates or this Agreement may be
served; provided, however, that, if it shall be necessary that the Trustee
maintain an office or agency in another location (e.g., the Certificates shall
be represented by Definitive Certificates and shall be listed on a national
securities exchange), the Trustee will make all reasonable efforts to establish
such an office or agency. Written notice of the location of each such other
office or agency and of any change of location thereof shall be given by the
Trustee to the Company, the Owner Trustees, the Loan Trustees (in the case of
any Owner Trustee or Loan Trustee, at its address specified in the Financing
Documents or such other address as may be notified to the Trustee) and the
Certificateholders. In the event that no such office or agency shall be
maintained or no such notice of location or of change of location shall be
given, presentations and demands may be made and notices may be served at the
Corporate Trust Office of the Trustee.

                  (b) There shall at all times be a Registrar and a Paying Agent
hereunder with respect to the Certificates. Each such Authorized Agent shall be
a bank or trust company, shall be a corporation organized and doing business
under the laws of the United States or any state, with a combined capital and
surplus of at least $75,000,000, or, if the Trustee shall be acting as the
Registrar or Paying Agent hereunder, a corporation having a combined capital and
surplus in excess of $5,000,000, the obligations of which are guaranteed by a
corporation organized and doing business under the laws of the United States or
any state, with a combined capital and surplus of at least $75,000,000, and
shall be authorized under such laws to exercise corporate trust powers, subject
to supervision by Federal or state authorities. The Trustee shall initially be
the Paying Agent and, as provided in Section 3.04, Registrar hereunder with
respect to the Certificates. Each Registrar shall furnish to the Trustee, at
stated intervals of not more than six months, and at such other times as the
Trustee may request in writing, a copy of the Register maintained by such
Registrar.
<PAGE>   50
                                      -45-


                  (c) Any corporation into which any Authorized Agent may be
merged or converted or with which it may be consolidated, or any corporation
resulting from any merger, consolidation or conversion to which any Authorized
Agent shall be a party, or any corporation succeeding to the corporate trust
business of any Authorized Agent, shall be the successor of such Authorized
Agent hereunder, if such successor corporation is otherwise eligible under this
Section, without the execution or filing of any paper or any further act on the
part of the parties hereto or such Authorized Agent or such successor
corporation.

                  (d) Any Authorized Agent may at any time resign by giving
written notice of resignation to the Trustee, the Company, the Owner Trustees
and the Loan Trustees. The Company may, and at the request of the Trustee shall,
at any time terminate the agency of any Authorized Agent by giving written
notice of termination to such Authorized Agent and to the Trustee. Upon the
resignation or termination of an Authorized Agent or in case at any time any
such Authorized Agent shall cease to be eligible under this Section (when, in
either case, no other Authorized Agent performing the functions of such
Authorized Agent shall have been appointed), the Company shall promptly appoint
one or more qualified successor Authorized Agents, reasonably satisfactory to
the Trustee, to perform the functions of the Authorized Agent which has resigned
or whose agency has been terminated or who shall have ceased to be eligible
under this Section. The Company shall give written notice of any such
appointment made by it to the Trustee, the Owner Trustees and the Loan Trustees;
and in each case the Trustee shall mail notice of such appointment to all
Certificateholders as their names and addresses appear on the Register.

                  (e) The Company agrees to pay, or cause to be paid, from time
to time to each Authorized Agent reasonable compensation for its services and to
reimburse it for its reasonable expenses as set forth in the letter agreement
referred to in Section 7.07 hereof.

                  Section 7.13. Money for Certificate Payments to Be Held in
Trust. All moneys deposited with any Paying Agent for the purpose of any payment
on Certificates shall be deposited and held in trust for the benefit of the
Certificateholders entitled to such payment, subject to the provisions of this
Section. Moneys so deposited and held in trust shall constitute a separate trust
fund for the benefit of the Certificateholders with respect to which such money
was deposited.

                  The Trustee may at any time, for the purpose of obtaining the
satisfaction and discharge of this Agreement or for any other purpose, direct
any Paying Agent to pay to the Trustee all sums held in trust by such Paying
Agent, such sums to be held by the Trustee upon the same trusts as those upon
which such sums were held by such Paying Agent; and, upon such payment by any
Paying Agent to the Trustee, such Paying Agent shall be released from all
further liability with respect to such money.

                  Section 7.14. Registration of Equipment Notes in Name of
Subordination Agent. The Trustee agrees that all Equipment Notes to be purchased
by the Trust shall be issued in the name of the Subordination Agent or its
nominee and held by the Subordination Agent in trust for the benefit of the
Certificateholders, or, if not so held, the Subordination Agent or its nominee
shall be reflected as the owner of such Equipment Notes in the register of the
issuer of such Equipment Notes.
<PAGE>   51
                                      -46-


                  Section 7.15. Representations and Warranties of Trustee. The
Trustee hereby represents and warrants that:

                  (a) the Trustee is a Delaware banking corporation organized
and validly existing in good standing under the laws of the State of Delaware;

                  (b) the Trustee has full power, authority and legal right to
execute, deliver, and perform this Agreement, the Intercreditor Agreement, the
Registration Rights Agreement, the Escrow Agreement, the Note Purchase Agreement
and the Financing Documents to which it is a party and has taken all necessary
action to authorize the execution, delivery, and performance by it of this
Agreement, the Intercreditor Agreement, the Registration Rights Agreement, the
Escrow Agreement, the Note Purchase Agreement and the Financing Documents to
which it is a party;

                  (c) the execution, delivery and performance by the Trustee of
this Agreement, the Intercreditor Agreement, the Registration Rights Agreement,
the Escrow Agreement, the Note Purchase Agreement and the Financing Documents to
which it is a party (i) will not violate any provision of United States federal
law or the law of the state of the United States where it is located governing
the banking and trust powers of the Trustee or any order, writ, judgment, or
decree of any court, arbitrator or governmental authority applicable to the
Trustee or any of its assets, (ii) will not violate any provision of the
articles of association or by-laws of the Trustee, or (iii) will not violate any
provision of, or constitute, with or without notice or lapse of time, a default
under, or result in the creation or imposition of any lien on any properties
included in the Trust Property pursuant to the provisions of any mortgage,
indenture, contract, agreement or other undertaking to which it is a party,
which violation, default or lien could reasonably be expected to have an adverse
effect on the Trustee's performance or ability to perform its duties hereunder
or thereunder or on the transactions contemplated herein or therein;

                  (d) the execution, delivery and performance by the Trustee of
this Agreement, the Intercreditor Agreement, the Registration Rights Agreement,
the Escrow Agreement, the Note Purchase Agreement, and the Financing Documents
to which it is a party will not require the authorization, consent, or approval
of, the giving of notice to, the filing or registration with, or the taking of
any other action in respect of, any governmental authority or agency of the
United States or the state of the United States where it is located regulating
the banking and corporate trust activities of the Trustee; and

                  (e) this Agreement, the Intercreditor Agreement, the
Registration Rights Agreement, the Escrow Agreement, the Note Purchase
Agreement, and the Financing Documents to which it is a party have been duly
executed and delivered by the Trustee and constitute the legal, valid, and
binding agreements of the Trustee, enforceable against it in accordance with
their respective terms, provided that enforceability may be limited by (i)
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws
affecting the rights of creditors generally and (ii) general principles of
equity, regardless of whether applied in a proceeding in equity or at law.

                  Section 7.16. Withholding Taxes, Information Reporting. The
Trustee, as trustee of the grantor trust created by this Agreement, shall
exclude and withhold from each
<PAGE>   52
                                      -47-


distribution of principal, premium, if any, and interest and other amounts due
under this Agreement or under the Certificates any and all withholding taxes
applicable thereto as required by law. In addition, the Trustee shall remit such
amounts as would be required by Section 1446 of the Internal Revenue Code of
1986, as amended, if the Trust were characterized as a partnership engaged in a
U.S. trade or business for U.S. federal income tax purposes and shall withhold
such amounts from amounts distributable to or for the benefit of
Certificateholders or Investors that are not United States persons within the
meaning of Section 7701(a)(30) of the Internal Revenue Code of 1986, as amended.
In this regard, the Trustee shall cause the appropriate withholding agent to
withhold with respect to such distributions in the manner contemplated by
Section 10.04 of Revenue Procedure 89-31 and Treasury Regulation 1.1445-8(b)(3)
by filing a notice with the National Association of Securities Dealers, Inc.
substantially in the form of Exhibit E hereto on or before the date 10 days
prior to the Record Date. The Trustee shall mail such notice to the National
Association of Securities Dealers no later than the date than 15 days prior to
the Record Date. Investors that are not United States Persons agree to furnish a
United States taxpayer identification number ("TIN") to the Trustee and the
Trustee shall provide such TINs to the appropriate withholding agent. The
Trustee agrees to act as such withholding agent (except to the extent
contemplated above with respect to withholding amounts as if the Trust were
characterized as a partnership engaged in a U.S. trade or business for U.S.
federal income tax purposes) and, in connection therewith, whenever any present
or future taxes or similar charges are required to be withheld with respect to
any amounts payable in respect of the Certificates, to withhold such amounts and
timely pay the same to the appropriate authority in the name of and on behalf of
the Certificateholders, that it will file any necessary withholding tax returns
or statements when due, and that, as promptly as possible after the payment
thereof, it will deliver to each such Certificateholder appropriate
documentation showing the payment thereof, together with such additional
documentary evidence as such Certificateholders may reasonably request from time
to time. The Trustee agrees to file any other information reports as it may be
required to file under United States law. Each Certificateholder or Investor
that is not a United States person within the meaning of Section 7701(a)(30) of
the Internal Revenue Code, as amended, by its acceptance of a Certificate or a
beneficial interest therein, agrees to indemnify and hold harmless the Trust and
the Trustee from and against any improper failure to withhold taxes from amounts
payable to it or for its benefit, other than an improper failure attributable to
the gross negligence or willful misconduct of the Trustee.

                  Section 7.17. Trustee's Liens. The Trustee in its individual
capacity agrees that it will at its own cost and expense promptly take any
action as may be necessary to duly discharge and satisfy in full any mortgage,
pledge, lien, charge, encumbrance, security interest or claim ("Trustee's
Liens") on or with respect to the Trust Property which is attributable to the
Trustee either (i) in its individual capacity and which is unrelated to the
transactions contemplated by this Agreement, the Intercreditor Agreement, the
Note Purchase Agreement or the Financing Documents, or (ii) as Trustee hereunder
or in its individual capacity and which arises out of acts or omissions on the
part of the Trustee which are not contemplated by this Agreement.

                  Section 7.18. Preferential Collection of Claims. The Trustee
shall comply with Section 311(a) of the Trust Indenture Act, excluding any
creditor relationship listed in
<PAGE>   53
                                      -48-


Section 311(b) of the Trust Indenture Act. If the Trustee shall resign or be
removed as Trustee, it shall be subject to Section 311(a) of the Trust Indenture
Act to the extent provided therein.

                                  ARTICLE VIII

                CERTIFICATEHOLDERS' LISTS AND REPORTS BY TRUSTEE

                  Section 8.01. The Company to Furnish Trustee with Names and
Addresses of Certificateholders. The Company will furnish to the Trustee within
15 days after each Record Date with respect to a Scheduled Payment, and at such
other times as the Trustee may request in writing within 30 days after receipt
by the Company of any such request, a list, in such form as the Trustee may
reasonably require, of all information in the possession or control of the
Company as to the names and addresses of the Certificateholders, in each case as
of a date not more than 15 days prior to the time such list is furnished;
provided, however, that so long as the Trustee is the sole Registrar, no such
list need be furnished; and provided further, however, that no such list need be
furnished for so long as a copy of the Register is being furnished to the
Trustee pursuant to Section 7.12.

                  Section 8.02. Preservation of Information; Communications to
Certificateholders. The Trustee shall preserve, in as current a form as is
reasonably practicable, the names and addresses of Certificateholders contained
in the most recent list furnished to the Trustee as provided in Section 7.12 or
Section 8.01, as the case may be, and the names and addresses of
Certificateholders received by the Trustee in its capacity as Registrar, if so
acting. The Trustee may destroy any list furnished to it as provided in Section
7.12 or Section 8.01, as the case may be, upon receipt of a new list so
furnished.

                  Section 8.03. Reports by Trustee. Within 60 days after May 15
of each year commencing with the first full year following the issuance of the
Certificates, the Trustee shall transmit to the Certificateholders, as provided
in Section 313(c) of the Trust Indenture Act, a brief report dated as of such
May 15, if required by Section 313(a) of the Trust Indenture Act.

                  Section 8.04. Reports by the Company. The Company shall:

                  (a) file with the Trustee, within 30 days after the Company is
         required to file the same with the SEC, copies of the annual reports
         and of the information, documents and other reports (or copies of such
         portions of any of the foregoing as the SEC may from time to time by
         rules and regulations prescribe) which the Company is required to file
         with the SEC pursuant to Section 13 or Section 15(d) of the Securities
         Exchange Act of 1934, as amended; or, if the Company is not required to
         file information, documents or reports pursuant to either of such
         sections, then to file with the Trustee and the SEC, in accordance with
         rules and regulations prescribed by the SEC, such of the supplementary
         and periodic information, documents and reports which may be required
         pursuant to Section 13 of the Securities Exchange Act of 1934, as
         amended, in respect of a security listed and registered on a national
         securities exchange as may be prescribed in such rules and regulations;
<PAGE>   54
                                      -49-


                  (b) during any period, prior to the consummation of the
         Exchange Offer and during which the Shelf Registration Statement is not
         in effect, in which the Company is not subject to Section 13(a), 13(c)
         or 15(d) under the Securities Exchange Act of 1934, make available to
         any Holder of the Certificates in connection with any sale thereof and
         any prospective purchaser of the Certificates from such Holder, in each
         case upon request, the information specified in, and meeting the
         requirements of, Rule 144A(d)(4) under the Securities Act but only for
         so long as any of the Certificates remain outstanding and are
         "restricted securities" within the meaning of Rule 144(a)(3) under the
         Securities Act and, in any event, only until the second anniversary of
         the Issuance Date;

                  (c) file with the Trustee and the SEC, in accordance with the
         rules and regulations prescribed by the SEC, such additional
         information, documents and reports with respect to compliance by the
         Company with the conditions and covenants provided for in this
         Agreement, as may be required by such rules and regulations, including,
         in the case of annual reports, if required by such rules and
         regulations, certificates or opinions of independent public
         accountants, conforming to the requirements of Section 1.02;

                  (d) transmit to all Certificateholders, in the manner and to
         the extent provided in Section 313(c) of the Trust Indenture Act such
         summaries of any information, documents and reports required to be
         filed by the Company pursuant to subsections (a) and (c) of this
         Section 8.04 as may be required by rules and regulations prescribed by
         the SEC; and

                  (e) furnish to the Trustee, not less often than annually, a
         brief certificate from the principal executive officer, principal
         financial officer, any Vice President (or more senior ranking officer)
         or the principal accounting officer as to his or her knowledge of the
         Company's compliance with all conditions and covenants under this
         Agreement (it being understood that for purposes of this paragraph (e),
         such compliance shall be determined without regard to any period of
         grace or requirement of notice provided under this Agreement).

                                   ARTICLE IX

                             SUPPLEMENTAL AGREEMENTS

                  Section 9.01. Supplemental Agreements Without Consent of
Certificateholders. Without the consent of the Certificateholders, the Company
may (but will not be required to), and the Trustee (subject to Section 9.03)
shall, at the Company's request, at any time and from time to time, enter into
one or more agreements supplemental hereto or, if applicable, to the
Intercreditor Agreement, the Escrow Agreement, the Note Purchase Agreement, the
Deposit Agreement, the Registration Rights Agreement or any Liquidity Facility
in form satisfactory to the Trustee, for any of the following purposes:

                  (1) to evidence the succession of another corporation to the
         Company and the assumption by any such successor of the covenants of
         the Company herein contained or of the Company's obligations under the
         Note Purchase Agreement, the Registration Rights Agreement or any
         Liquidity Facility; or
<PAGE>   55
                                      -50-


                  (2) to add to the covenants of the Company for the benefit of
         the Certificateholders, or to surrender any right or power conferred
         upon the Company in this Agreement, the Note Purchase Agreement, the
         Registration Rights Agreement or any Liquidity Facility; or

                  (3) to correct or supplement any provision in this Agreement,
         the Intercreditor Agreement, the Escrow Agreement, the Deposit
         Agreement, the Note Purchase Agreement, the Registration Rights
         Agreement or any Liquidity Facility which may be defective or
         inconsistent with any other provision herein or therein or to cure any
         ambiguity or correct any mistake or to modify any other provision with
         respect to matters or questions arising under this Agreement, the
         Escrow Agreement, the Deposit Agreement, the Note Purchase Agreement,
         the Intercreditor Agreement, the Registration Rights Agreement or any
         Liquidity Facility, provided that any such action shall not materially
         adversely affect the interests of the Certificateholders; or

                  (4) to comply with any requirement of the SEC, any applicable
         law, rules or regulations of any exchange or quotation system on which
         the Certificates are listed, any regulatory body or the Registration
         Rights Agreement to effectuate the Exchange Offer; or

                  (5) to modify, eliminate or add to the provisions of this
         Agreement to such extent as shall be necessary to continue the
         qualification of this Agreement (including any supplemental agreement)
         under the Trust Indenture Act or under any similar Federal statute
         hereafter enacted, and to add to this Agreement such other provisions
         as may be expressly permitted by the Trust Indenture Act, excluding,
         however, the provisions referred to in Section 316(a)(2) of the Trust
         Indenture Act as in effect at the date as of which this instrument was
         executed or any corresponding provision in any similar Federal statute
         hereafter enacted; or

                  (6) to evidence and provide for the acceptance of appointment
         under this Agreement by the Trustee of a successor Trustee and to add
         to or change any of the provisions of this Agreement as shall be
         necessary to provide for or facilitate the administration of the Trust,
         pursuant to the requirements of Section 7.10; or

                  (7) to provide the information required under Section 7.12 and
         Section 12.03 as to the Trustee; or

                  (8) to modify or eliminate provisions relating to the transfer
         or exchange of Exchange Certificates or the Initial Certificates upon
         consummation of the Exchange Offer (as defined in the Registration
         Rights Agreement) or effectiveness of the Shelf Registration Statement
         or the Exchange Offer Registration Statement;

provided, however, that no such supplemental agreement shall adversely affect
the status of any Trust as a grantor trust under Subpart E, Part I of Subchapter
J of Chapter 1 of Subtitle A of the Internal Revenue Code of 1986, as amended,
for U.S. federal income tax purposes.

                  Section 9.02. Supplemental Agreements with Consent of
Certificateholders. With the consent of the Certificateholders holding
Certificates (including consents obtained in
<PAGE>   56
                                      -51-


connection with a tender offer or exchange offer for the Certificates)
evidencing Fractional Undivided Interests aggregating not less than a majority
in interest in the Trust, by Direction of said Certificateholders delivered to
the Company and the Trustee, the Company may (with the consent of the Owner
Trustees, if any, which consent shall not be unreasonably withheld), and the
Trustee (subject to Section 9.03) shall, enter into an agreement or agreements
for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Agreement, the Intercreditor
Agreement, any Liquidity Facility, the Registration Rights Agreement, the Escrow
Agreement, the Deposit Agreement or the Note Purchase Agreement to the extent
applicable to such Certificateholders or of modifying in any manner the rights
and obligations of such Certificateholders under this Agreement, the
Intercreditor Agreement, any Liquidity Facility, the Registration Rights
Agreement, the Escrow Agreement, the Deposit Agreement or the Note Purchase
Agreement to the extent applicable to such Certificateholders or of modifying in
any manner the rights and obligations of such Certificateholders under this
Agreement, the Intercreditor Agreement, any Liquidity Facility, the Registration
Rights Agreement, the Escrow Agreement, the Deposit Agreement or the Note
Purchase Agreement; provided, however, that no such agreement shall, without the
consent of the Certificateholder of each Outstanding Certificate affected
thereby:

                  (1) reduce in any manner the amount of, or delay the timing
         of, any receipt by the Trustee (or, with respect to the Deposits, the
         Certificateholders) of payments on the Equipment Notes held in the
         Trust or on the Deposits or distributions that are required to be made
         herein on any Certificate, or change any date of payment on any
         Certificate, or change the place of payment where, or the coin or
         currency in which, any Certificate is payable, or impair the right to
         institute suit for the enforcement of any such payment or distribution
         on or after the Regular Distribution Date or Special Distribution Date
         applicable thereto; or

                  (2) permit the disposition of any Equipment Note included in
         the Trust Property except as permitted by this Agreement, or otherwise
         deprive such Certificateholder of the benefit of the ownership of the
         Equipment Notes in the Trust; or

                  (3) reduce the specified percentage of the aggregate
         Fractional Undivided Interests of the Trust which is required for any
         such supplemental agreement, or reduce such specified percentage
         required for any waiver of compliance with certain provisions of this
         Agreement or certain defaults hereunder and their consequences provided
         for in this Agreement; or

                  (4) waive, amend or modify Section 2.4, 3.2 or 3.3 of the
         Intercreditor Agreement in a manner adverse to the Certificateholders;
         or

                  (5) modify any of the provisions of this Section 9.02 or
         Section 6.05, except to increase any such percentage or to provide that
         certain other provisions of this Agreement cannot be modified or waived
         without the consent of the Certificateholder of each Certificate
         affected thereby; or
<PAGE>   57
                                      -52-


                  (6) adversely affect the status of any Trust as a grantor
         trust under Subpart E, Part I of Subchapter J of Chapter 1 of Subtitle
         A of the Internal Revenue Code of 1986, as amended, for U.S. federal
         income tax purposes.

                  It shall not be necessary for any Direction of
Certificateholders under this Section to approve the particular form of any
proposed supplemental agreement, but it shall be sufficient if such Direction
shall approve the substance thereof.

                  Section 9.03. Documents Affecting Immunity or Indemnity.
Except for the performance of its covenants herein, if in the opinion of the
Trustee any document required to be executed by it pursuant to the terms of
Section 9.01 or 9.02 affects adversely any interest, right, duty, immunity or
indemnity in favor of the Trustee under this Agreement, the Trustee may in its
discretion decline to execute such document.

                  Section 9.04. Execution of Supplemental Agreements. In
executing, or accepting the additional trusts created by, any agreement
permitted by this Article or the modifications thereby of the trusts created by
this Agreement, the Trustee shall be entitled to receive, and shall be fully
protected in relying upon, an Opinion of Counsel stating that the execution of
such supplemental agreement is authorized or permitted by this Agreement.

                  Section 9.05. Effect of Supplemental Agreements. Upon the
execution of any agreement supplemental to this Agreement under this Article,
this Agreement shall be modified in accordance therewith, and such supplemental
agreement shall form a part of this Agreement for all purposes; and every Holder
of a Certificate theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

                  Section 9.06. Conformity with Trust Indenture Act. Every
supplemental agreement executed pursuant to this Article shall conform to the
requirements of the Trust Indenture Act as then in effect.

                  Section 9.07. Reference in Certificates to Supplemental
Agreements. Certificates authenticated and delivered after the execution of any
supplemental agreement pursuant to this Article may bear a notation in form
approved by the Trustee as to any matter provided for in such supplemental
agreement; and, in such case, suitable notation may be made upon Outstanding
Certificates after proper presentation and demand.

                                    ARTICLE X

                AMENDMENTS TO INDENTURES AND FINANCING DOCUMENTS

                  Section 10.01. Amendments and Supplements to Indentures and
Financing Documents. In the event that the Trustee, as holder (or beneficial
owner through the Subordination Agent) of any Equipment Note in trust for the
benefit of the Certificateholders or as Controlling Party under the
Intercreditor Agreement, receives (directly or indirectly through the
Subordination Agent) a request for a consent to any amendment, modification,
waiver or supplement under any Indenture, any other Financing Document, any
Equipment Note or any other related document, the Trustee shall forthwith send a
notice of such proposed amendment,
<PAGE>   58
                                      -53-


modification, waiver or supplement to each Certificateholder registered on the
Register as of the date of such notice. The Trustee shall request from the
Certificateholders a Direction as to (a) whether or not to take or refrain from
taking (or direct the Subordination Agent to take or refrain from taking) any
action which a holder of such Equipment Note has the option to direct, (b)
whether or not to give or execute (or direct the Subordination Agent to give or
execute) any waivers, consents, amendments, modifications or supplements as a
holder of such Equipment Note or a Controlling Party and (c) how to vote (or
direct the Subordination Agent to vote) any Equipment Note if a vote has been
called for with respect thereto. Provided such a request for Certificateholder
Direction shall have been made, in directing any action or casting any vote or
giving any consent as the holder of any Equipment Note (or in directing the
Subordination Agent in any of the foregoing), (i) other than as Controlling
Party, the Trustee shall vote for or give consent to any such action with
respect to such Equipment Note in the same proportion as that of (A) the
aggregate face amounts of all Certificates actually voted in favor of or for
giving consent to such action by such Direction of Certificateholders to (B) the
aggregate face amount of all Outstanding Certificates and (ii) as Controlling
Party, the Trustee shall vote as directed in such Certificateholder Direction by
the Certificateholders evidencing a Fractional Undivided Interest aggregating
not less than a majority in interest in the Trust. For purposes of the
immediately preceding sentence, a Certificate shall have been "actually voted"
if the Holder of such Certificate has delivered to the Trustee an instrument
evidencing such Holder's consent to such Direction prior to two Business Days
before the Trustee directs such action or casts such vote or gives such consent.
Notwithstanding the foregoing, but subject to Section 6.04 and the Intercreditor
Agreement, the Trustee may, in its own discretion and at its own direction,
consent and notify the relevant Loan Trustee of such consent (or direct the
Subordination Agent to consent and notify the Loan Trustee of such consent) to
any amendment, modification, waiver or supplement under the relevant Indenture,
any other Financing Document, any Equipment Note or any other related document,
if an Event of Default hereunder shall have occurred and be continuing, or if
such amendment, modification, waiver or supplement will not materially adversely
affect the interests of the Certificateholders.

                                   ARTICLE XI

                              TERMINATION OF TRUST

                  Section 11.01. Termination of the Trust. The respective
obligations and responsibilities of the Company and the Trustee with respect to
the Trust shall terminate upon the earlier of (A) the completion of the
assignment, transfer and discharge described in the first sentence of the
immediately following paragraph and (B) distribution to all Holders of
Certificates and the Trustee of all amounts required to be distributed to them
pursuant to this Agreement and the disposition of all property held as part of
the Trust Property; provided, however, that in no event shall the Trust continue
beyond one hundred ten (110) years following the date of the earliest execution
of this Trust Agreement.

                  Upon the earlier of (i) the first Business Day after November
30, 1999, or, if later, the fifth Business Day following the Delivery Period
Termination Date and (ii) the fifth Business Day following the date on which a
Triggering Event occurs (such date, the "Transfer Date"), or, if later the date
on which all of the conditions set forth in the immediately following sentence
<PAGE>   59
                                      -54-


have been satisfied, the Trustee is hereby directed (subject only to the
immediately following sentence) to, and the Company shall direct the institution
that will serve as the Related Trustee under the Related Pass Through Trust
Agreement to, execute and deliver the Assignment and Assumption Agreement,
pursuant to which the Trustee shall assign, transfer and deliver all of the
Trustee's right, title and interest to the Trust Property to the Related Trustee
under the Related Pass Through Trust Agreement. The Trustee and the Related
Trustee shall execute and deliver the Assignment and Assumption Agreement upon
the satisfaction of the following conditions:

                  (i) The Trustee, the Related Trustee and each of the Rating
         Agencies then rating the Certificates shall have received an Officer's
         Certificate and an Opinion of Counsel dated the date of the Assignment
         and Assumption Agreement and each satisfying the requirements of
         Section 1.02, which Opinion of Counsel shall be substantially to the
         effect set forth below and may be relied upon by the Beneficiaries (as
         defined in the Assignment and Assumption Agreement):

                  (a)      upon the execution and delivery thereof by the
                           parties thereto in accordance with the terms of this
                           Agreement and the Related Pass Through Trust
                           Agreement, the Assignment and Assumption Agreement
                           will constitute the valid and binding obligation of
                           each of the parties thereto enforceable against each
                           such party in accordance with its terms;

                  (b)      upon the execution and delivery of the Assignment and
                           Assumption Agreement in accordance with the terms of
                           this Agreement and the Related Pass Through Trust
                           Agreement, each of the Certificates then Outstanding
                           will be entitled to the benefits of the Related Pass
                           Through Trust Agreement;

                  (c)      the Related Trust is not required to be registered as
                           an investment company under the Investment Company
                           Act of 1940, as amended;

                  (d)      the Related Pass Through Trust Agreement constitutes
                           the valid and binding obligation of the Company
                           enforceable against the Company in accordance with
                           its terms; and

                  (e)      neither the execution and delivery of the Assignment
                           and Assumption Agreement in accordance with the terms
                           of this Agreement and the Related Pass Through Trust
                           Agreement, nor the consummation by the parties
                           thereto of the transactions contemplated to be
                           consummated thereunder on the date thereof, will
                           violate any law or governmental rule or regulation of
                           the State of New York or the United States of America
                           known to such counsel to be applicable to the
                           transactions contemplated by the Assignment and
                           Assumption Agreement.

                  (ii) The Trustee and the Company shall have received (x) a
         copy of the articles of incorporation and bylaws of the Related Trustee
         certified as of the Transfer Date by the Secretary or Assistant
         Secretary of such institution and (y) a copy of the filing (including
         all attachments thereto) made by the institution serving as the Related
         Trustee with the
<PAGE>   60
                                      -55-


         Office of the Superintendent, State of New York Banking Department for
         the qualification of the Related Trustee under Section 131(3) of the
         New York Banking Law.

Upon the execution of the Assignment and Assumption Agreement by the parties
thereto, the Trust shall be terminated, the Certificateholders shall receive
beneficial interests in the Related Trust in exchange for their interests in the
Trust equal to their respective beneficial interests in the Trust, and the
Outstanding Certificates representing Fractional Undivided Interests in the
Trust shall be deemed for all purposes of this Agreement and the Related Pass
Through Trust Agreement, without further signature or action of any party or
Certificateholder, to be certificates representing the same fractional undivided
interests in the Related Trust and its trust property. By acceptance of its
Certificate, each Certificateholder consents to such assignment, transfer and
delivery of the Trust Property to the trustee of the Related Trust upon the
execution and delivery of the Assignment and Assumption Agreement.

                  In connection with the occurrence of the event set forth in
clause (B) above, notice of such termination, specifying the Distribution Date
upon which the Certificateholders may surrender their Certificates to the
Trustee for payment of the final distribution and cancellation, shall be mailed
promptly by the Trustee to Certificateholders not earlier than the 60th day and
not later than the 20th day next preceding such final Distribution Date
specifying (A) the Distribution Date upon which the proposed final payment of
the Certificates will be made upon presentation and surrender of Certificates at
the office or agency of the Trustee therein specified, (B) the amount of any
such proposed final payment, and (C) that the Record Date otherwise applicable
to such Distribution Date is not applicable, payments being made only upon
presentation and surrender of the Certificates at the office or agency of the
Trustee therein specified. The Trustee shall give such notice to the Registrar
at the time such notice is given to Certificateholders. Upon presentation and
surrender of the Certificates in accordance with such notice, the Trustee shall
cause to be distributed to Certificateholders such final payments.

                  In the event that all of the Certificateholders shall not
surrender their Certificates for cancellation within six months after the date
specified in the above-mentioned written notice, the Trustee shall give a second
written notice to the remaining Certificateholders to surrender their
Certificates for cancellation and receive the final distribution with respect
thereto. No additional interest shall accrue on the Certificates after the
Distribution Date specified in the first written notice. In the event that any
money held by the Trustee for the payment of distributions on the Certificates
shall remain unclaimed for two years (or such lesser time as the Trustee shall
be satisfied, after sixty days' notice from the Company, is one month prior to
the escheat period provided under applicable law) after the final distribution
date with respect thereto, the Trustee shall pay to each Loan Trustee the
appropriate amount of money relating to such Loan Trustee and shall give written
notice thereof to the related Owner Trustees, the Owner Participants and the
Company.

                                   ARTICLE XII

                            MISCELLANEOUS PROVISIONS

                  Section 12.01. Limitation on Rights of Certificateholders. The
death or incapacity of any Certificateholder shall not operate to terminate this
Agreement or the Trust, nor entitle
<PAGE>   61
                                      -56-


such Certificateholder's legal representatives or heirs to claim an accounting
or to take any action or commence any proceeding in any court for a partition or
winding up of the Trust, nor otherwise affect the rights, obligations, and
liabilities of the parties hereto or any of them.

                  Section 12.02. Certificates Nonassessable and Fully Paid.
Except as set forth in the last sentence of this Section 12.02,
Certificateholders shall not be personally liable for obligations of the Trust,
the Fractional Undivided Interests represented by the Certificates shall be
nonassessable for any losses or expenses of the Trust or for any reason
whatsoever, and Certificates, upon authentication thereof by the Trustee
pursuant to Section 3.03, are and shall be deemed fully paid. No
Certificateholder shall have any right (except as expressly provided herein) to
vote or in any manner otherwise control the operation and management of the
Trust Property, the Trust, or the obligations of the parties hereto, nor shall
anything set forth herein, or contained in the terms of the Certificates, be
construed so as to constitute the Certificateholders from time to time as
partners or members of an association. Neither the existence of the Trust nor
any provision herein is intended to or shall limit the liability the
Certificateholders would otherwise incur if the Certificateholders owned Trust
Property as co-owners, or incurred any obligations of the Trust, directly rather
than through the Trust.

                  Section 12.03. Notices. (a) Unless otherwise specifically
provided herein, all notices required under the terms and provisions of this
Agreement shall be in English and in writing, and any such notice may be given
by United States mail, courier service or telecopy, and any such notice shall be
effective when received or, if made, given, furnished or filed by facsimile or
telecommunication transmission, when received unless received outside of
business hours, in which case on the next open of business on a Business Day,

                  if to the Company, to:

                           America West Airlines, Inc.
                           4000 East Sky Harbor Boulevard
                           Phoenix, Arizona  85043

                           Attention:  Vice President-
                                       Treasurer
                           Facsimile:  (602) 693-5886

                  if to the Trustee, to:

                           Wilmington Trust Company
                           Rodney Square North
                           1100 North Market Street
                           Wilmington, Delaware  19890-0001

                           Attention:  Corporate Trust Department
                           Facsimile:  (302) 651-8882
                           Telephone:   (302) 651-8584
<PAGE>   62
                                      -57-


                  (b) The Company or the Trustee, by notice to the other, may
designate additional or different addresses for subsequent notices or
communications.

                  (c) Any notice or communication to Certificateholders shall be
mailed by first-class mail to the addresses for Certificateholders shown on the
Register kept by the Registrar. Failure so to mail a notice or communication or
any defect in such notice or communication shall not affect its sufficiency with
respect to other Certificateholders.

                  (d) If a notice or communication is mailed in the manner
provided above within the time prescribed, it is conclusively presumed to have
been duly given, whether or not the addressee receives it.

                  (e) If the Company mails a notice or communication to the
Certificateholders, it shall mail a copy to the Trustee and to the Paying Agent
at the same time.

                  (f) Notwithstanding the foregoing, all communications or
notices to the Trustee shall be deemed to be given only when received by a
Responsible Officer of the Trustee.

                  (g) The Trustee shall promptly furnish the Company with a copy
of any demand, notice or written communication received by the Trustee hereunder
from any Certificateholder, Owner Trustee or Loan Trustee.

                  Section 12.04. Governing Law. THIS AGREEMENT HAS BEEN
DELIVERED IN THE STATE OF DELAWARE AND THIS AGREEMENT AND THE CERTIFICATES SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
DELAWARE AND THE OBLIGATIONS, RIGHTS AND REMEDIES OF THE PARTIES HEREUNDER SHALL
BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

                  Section 12.05. Severability of Provisions. If any one or more
of the covenants, agreements, provisions or terms of this Agreement shall be for
any reason whatsoever held invalid, then such covenants, agreements, provisions,
or terms shall be deemed severable from the remaining covenants, agreements,
provisions or terms of this Agreement and shall in no way affect the validity or
enforceability of the other provisions of this Agreement or the Trust, or of the
Certificates or the rights of the Certificateholders thereof.

                  Section 12.06. Trust Indenture Act Controls. Upon the
occurrence of any Registration Event, this Agreement shall become subject to the
provisions of the Trust Indenture Act and shall, to the extent applicable, be
governed by such provisions. From and after any Registration Event, if any
provision of this Agreement limits, qualifies or conflicts with another
provision which is required to be included in this Agreement by the Trust
Indenture Act, the required provision shall control.

                  Section 12.07. Effect of Headings and Table of Contents. The
Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.
<PAGE>   63
                                      -58-


                  Section 12.08. Successors and Assigns. All covenants,
agreements, representations and warranties in this Agreement by the Trustee and
the Company shall bind and, to the extent permitted hereby, shall inure to the
benefit of and be enforceable by their respective successors and assigns,
whether so expressed or not.

                  Section 12.09. Benefits of Agreement. Nothing in this
Agreement or in the Certificates, express or implied, shall give to any Person,
other than the parties hereto and their successors hereunder, and the
Certificateholders, any benefit or any legal or equitable right, remedy or claim
under this Agreement.

                  Section 12.10. Legal Holidays. In any case where any Regular
Distribution Date or Special Distribution Date relating to any Certificate shall
not be a Business Day, then (notwithstanding any other provision of this
Agreement) payment need not be made on such date, but may be made on the next
succeeding Business Day with the same force and effect as if made on such
Regular Distribution Date or Special Distribution Date, and no interest shall
accrue during the intervening period.

                  Section 12.11. Counterparts. For the purpose of facilitating
the execution of this Agreement and for other purposes, this Agreement may be
executed simultaneously in any number of counterparts, each of which
counterparts shall be deemed to be an original, and all of which counterparts
shall constitute but one and the same instrument.

                  Section 12.12. Intention of Parties. The parties hereto intend
that the Trust be classified for U.S. federal income tax purposes as a grantor
trust under Subpart E, Part I of Subchapter J of the Internal Revenue Code of
1986, as amended, and not as a trust or association taxable as a corporation or
as a partnership. Each Certificateholder and Investor, by its acceptance of its
Certificate or a beneficial interest therein, agrees to treat the Trust as a
grantor trust for all U.S. federal, state and local income tax purposes. The
powers granted and obligations undertaken pursuant to this Agreement shall be so
construed so as to further such intent.
<PAGE>   64
                                      -59-



                  IN WITNESS WHEREOF, the parties have caused this Agreement to
be duly executed by their respective officers thereunto duly authorized as of
the day and year first written above.


                                       AMERICA WEST AIRLINES, INC.


                                       By:   /s/ W. Douglas Parker
                                             _______________________
                                             Name: W. Douglas Parker
                                             Title: Sr. Vice President & CFO


                                       WILMINGTON TRUST COMPANY,
                                             as Trustee


                                       By:   /s/ Jill K. Morrison
                                             _______________________
                                             Name: Jill K. Morrison
                                             Title: Administrative Account
                                                    Manager


<PAGE>   65
                                                                       EXHIBIT A

                               FORM OF CERTIFICATE

REGISTERED

No._________

         [THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT
         OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND ACCORDINGLY, MAY NOT BE
         OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
         BENEFIT OF, ANY PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.
         BY ITS ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A
         "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
         SECURITIES ACT), (B) IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS
         DEFINED IN RULE 501(a)(1), (2), (3) OR (7) OF REGULATION D UNDER THE
         SECURITIES ACT) (AN "INSTITUTIONAL ACCREDITED INVESTOR") OR (C) IT IS
         NOT A U.S. PERSON AND IS ACQUIRING THIS CERTIFICATE IN AN OFFSHORE
         TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER THE SECURITIES ACT;
         (2) AGREES THAT IT WILL NOT WITHIN TWO YEARS AFTER THE LATER OF THE
         ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS
         CERTIFICATE WAS HELD BY AMERICA WEST AIRLINES, INC., THE TRUSTEE OR ANY
         AFFILIATE OF ANY OF SUCH PERSONS RESELL OR OTHERWISE TRANSFER THIS
         CERTIFICATE EXCEPT (A) AMERICA WEST AIRLINES, INC., (B) TO A QUALIFIED
         INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES
         ACT, (C) OUTSIDE THE UNITED STATES IN AN OFFSHORE TRANSACTION IN
         COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT, (D) PURSUANT TO THE
         EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES
         ACT (IF AVAILABLE) OR (E) PURSUANT TO AN EFFECTIVE REGISTRATION
         STATEMENT UNDER THE SECURITIES ACT; AND (3) AGREES THAT IF IT SHOULD
         RESELL OR OTHERWISE TRANSFER THIS CERTIFICATE IT WILL DELIVER TO EACH
         PERSON TO WHOM THIS CERTIFICATE IS TRANSFERRED A NOTICE SUBSTANTIALLY
         TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF THIS
         CERTIFICATE WITHIN TWO YEARS AFTER THE LATER OF THE ORIGINAL ISSUANCE
         OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE WAS HELD
         BY AMERICA WEST AIRLINES, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY OF
         SUCH PERSONS, THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON
         THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT
         THIS CERTIFICATE TO THE TRUSTEE. AS USED HEREIN, THE TERMS "OFFSHORE
         TRANSACTION", "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN
         TO THEM BY REGULATION S UNDER THE SECURITIES ACT. THE PASS THROUGH
         TRUST AGREEMENT CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO
         REGISTER ANY
<PAGE>   66
                                      A-2


         TRANSFER OF THIS CERTIFICATE IN VIOLATION OF THE FOREGOING
         RESTRICTIONS.]*

         BY ITS ACQUISITION HEREOF, THE HOLDER REPRESENTS THAT (A) NO PLAN
         ASSETS HAVE BEEN USED TO PURCHASE THIS CERTIFICATE OR AN INTEREST
         HEREIN OR (B) THE PURCHASE AND HOLDING OF THIS CERTIFICATE OR AN
         INTEREST HEREIN IS EXEMPT FROM THE PROHIBITED TRANSACTION RESTRICTIONS
         OF ERISA AND THE CODE PURSUANT TO ONE OR MORE PROHIBITED TRANSACTION
         STATUTORY OR ADMINISTRATIVE EXEMPTIONS. THE PASS THROUGH TRUST
         AGREEMENT CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO
         REGISTER ANY TRANSFER OF THIS CERTIFICATE IN VIOLATION OF THE FOREGOING
         RESTRICTIONS.

         [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
         OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT,
         AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS CERTIFICATE IS
         REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
         REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT
         HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY
         AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE
         HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH
         AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         TRANSFERS OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO TRANSFERS IN
         WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR
         SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL
         CERTIFICATE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
         RESTRICTIONS SET FORTH IN SECTIONS 3.05 AND 3.06 OF THE PASS THROUGH
         TRUST AGREEMENT REFERRED TO HEREIN.]**

----------

         *        Not to be included on the face of the Regulation S Global
                  Certificate.

         **       To be included on the face of each Global Certificate.
<PAGE>   67
                                      A-3


                             [GLOBAL CERTIFICATE]*

           AMERICA WEST AIRLINES PASS THROUGH TRUST, SERIES 1998-1B-O

                7.12% America West Airlines [Initial] [Exchange]
                            Pass Through Certificate,
                                Series 1998-1B-O

                   Final Legal Distribution Date: July 2, 2018

evidencing a fractional undivided interest in a trust, the property of which
includes certain equipment notes each secured by an Aircraft leased to or owned
by America West Airlines, Inc.

                  $__________ Fractional Undivided Interest representing
                  .0.0024298974% of the Trust per $1,000 face amount

                  THIS CERTIFIES THAT _______________, for value received, is
the registered owner of a $________ (__________dollars) Fractional Undivided
Interest in the America West Airlines Pass Through Trust, Series 1998-1B-O (the
"Trust") created pursuant to a Pass Through Trust Agreement, dated as of October
6, 1998 (the "Agreement"), between Wilmington Trust Company (the "Trustee") and
America West Airlines, Inc., a corporation incorporated under Delaware law (the
"Company"), a summary of certain of the pertinent provisions of which is set
forth below. To the extent not otherwise defined herein, the capitalized terms
used herein have the meanings assigned to them in the Agreement. This
Certificate is one of the duly authorized Certificates designated as "7.12%
America West Airlines [Initial] [Exchange] Pass Through Certificates, Series
1998-1B-O" (herein called the "Certificates"). This Certificate is issued under
and is subject to the terms, provisions, and conditions of the Agreement. By
virtue of its acceptance hereof the Certificateholder of this Certificate
assents to and agrees to be bound by the provisions of the Agreement and the
Intercreditor Agreement. The property of the Trust includes an interest in
certain Equipment Notes and all rights of the Trust to receive payments under
the Intercreditor Agreement and any Liquidity Facility (the "Trust Property").
Each issue of the Equipment Notes is secured by, among other things, a security
interest in the Aircraft leased to or owned by the Company.

----------

         *        To be included on the face of each Global Certificate.
<PAGE>   68
                                      A-4


                  The Certificates represent fractional undivided interests in
the Trust and the Trust Property, and have no rights, benefits or interest in
respect of any assets or property other than the Trust Property.

                  Subject to and in accordance with the terms of the Agreement
and the Intercreditor Agreement, from and to the extent of funds then available
to the Trustee, there will be distributed on each January 2 and July 2 (a
"Regular Distribution Date"), commencing on January 2, 1999, to the Person in
whose name this Certificate is registered at the close of business on the 15th
day preceding the Regular Distribution Date, an amount in respect of the
Scheduled Payments due on such Regular Distribution Date on the Equipment Notes,
the receipt of which has been confirmed by the Trustee, equal to the product of
the percentage interest in the Trust evidenced by this Certificate and an amount
equal to the sum of such Scheduled Payments. Subject to and in accordance with
the terms of the Agreement and the Intercreditor Agreement, in the event that
Special Payments on the Equipment Notes are received by the Trustee, from funds
then available to the Trustee, there shall be distributed on the applicable
Special Distribution Date, to the Person in whose name this Certificate is
registered at the close of business on the 15th day preceding the Special
Distribution Date, an amount in respect of such Special Payments on the
Equipment Notes, the receipt of which has been confirmed by the Trustee, equal
to the product of the percentage interest in the Trust evidenced by this
Certificate and an amount equal to the sum of such Special Payments so received.
If a Regular Distribution Date or Special Distribution Date is not a Business
Day, distribution shall be made on the immediately following Business Day with
the same force and effect as if made on such Regular Distribution Date or
Special Distribution Date and no interest shall accrue during the intervening
period. The Trustee shall mail notice of each Special Payment and the Special
Distribution Date therefor to the Certificateholder of this Certificate.

                  The Certificates do not represent a direct obligation of, or
an obligation guaranteed by, or an interest in, the Company or the Trustee or
any of their affiliates. The Certificates are limited in right or payment, all
as more specifically set forth on the face hereof and in the Agreement. All
payments or distributions made to Certificateholders under the Agreement shall
be made only from the Trust Property and only to the extent that the Trustee
shall have sufficient income or proceeds from the Trust Property to make such
payments in accordance with the terms of the Agreement. Each Certificate-holder
of this Certificate, by its acceptance hereof, agrees that it will look solely
to the income and proceeds from the Trust Property to the extent available for
distribution to such Certificateholder as provided in the Agreement. This
Certificate does not purport to summarize the Agreement and reference is made to
the Agreement for information with respect to the interests, rights, benefits,
obligations, proceeds, and duties evidenced hereby. A copy of the Agreement may
be examined during normal business hours at the principal office of the Trustee,
and at such other places, if any, designated by the Trustee, by any
Certificateholder upon request.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Certificateholders under the
Agreement at any time by the Company and the Trustee with the consent of the
Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in the Trust. Any
such consent by the Certificateholder of this Certificate shall be conclusive
and binding on such Certificateholder and
<PAGE>   69
                                      A-5


upon all future Certificateholders of this Certificate and of any Certificate
issued upon the transfer hereof or in exchange hereof or in lieu hereof whether
or not notation of such consent is made upon this Certificate. The Agreement
also permits the amendment thereof, in certain limited circumstances, without
the consent of the Certificateholders of any of the Certificates.

                  As provided in the Agreement and subject to certain
limitations therein set forth, the transfer of this Certificate is registrable
in the Register upon surrender of this Certificate for registration of transfer
at the offices or agencies maintained by the Trustee in its capacity as
Registrar, or by any successor Registrar, in the Borough of Manhattan, the City
of New York, duly endorsed or accompanied by a written instrument of transfer in
form satisfactory to the Trustee and the Registrar duly executed by the
Certificateholder hereof or such Certificateholder's attorney duly authorized in
writing, and thereupon one or more new Certificates of authorized denominations
evidencing the same aggregate Fractional Undivided Interest in the Trust will be
issued to the designated transferee or transferees.

                  [The Holder of this Certificate is entitled to the benefits of
the Exchange and Registration Rights Agreement, dated as of October 6, 1998,
among the Company, the Trustee and the Initial Purchasers named therein (the
"Registration Rights Agreement"). In the event that no Registration Event has
occurred on or prior to the 210th day after the date of the issuance of the
Certificates, the interest rate per annum payable in respect of the Equipment
Notes and the Deposits shall be increased by 0.50%, from and including the 210th
day after the Issuance Date to but excluding the earlier of (i) the date on
which a Registration Event occurs and (ii) the date on which there cease to be
any Registrable Certificates (as defined in the Registration Rights Agreement).
In the event that the Shelf Registration Statement ceases to be effective at any
time during the period specified by Section 2(b)(B) of the Registration Rights
Agreement for more than 60 days, whether or not consecutive, during any 12-month
period, the interest rate per annum payable in respect of the Equipment Notes
and the Deposits shall be increased by 0.50% from the 61st day of the applicable
12-month period such Shelf Registration Statement ceases to be effective until
such time as the Shelf Registration Statement again becomes effective ( or, if
earlier, the end of the period specified by Section 2(b)(B) of the Registration
Rights Agreement).]*

                  Except as otherwise provided in the Agreement and
notwithstanding the above, the final distribution on this Certificate will be
made after notice mailed by the Trustee of the pendency of such distribution and
only upon presentation and surrender of this Certificate at the office or agency
of the Trustee specified in such notice.

                  Under certain circumstances set forth in Section 11.01 of the
Agreement, all of the Trustee's right, title and interest to the Trust Property
may be assigned, transferred and delivered to the Related Trustee of the Related
Trust pursuant to the Assignment and Assumption Agreement. Upon the
effectiveness of such Assignment and Assumption Agreement (the

         *        To be included only on each Initial Certificate.
<PAGE>   70
                                      A-6


"Transfer"), the Trust shall be terminated, the Certificateholders shall receive
beneficial interests in the Related Trust in exchange for their interests in the
Trust equal to their respective beneficial interests in the Trust, the
Certificates representing Fractional Undivided Interests in the Trust shall be
deemed for all purposes of the Agreement and the Related Pass Through Trust
Agreement to be certificates representing the same fractional undivided
interests in the Related Trust and its trust property. Each Certificateholder,
by its acceptance of this Certificate or a beneficial interest herein, agrees to
be bound by the Assignment and Assumption Agreement and subject to the terms of
the Related Pass Through Trust Agreement as a certificateholder thereunder. From
and after the Transfer, unless and to the extent the context otherwise requires,
references herein to the Trust, the Agreement and the Trustee shall constitute
references to the Related Trust, the Related Pass Through Trust Agreement and
trustee of the Related Trust, respectively.

                  The Certificates are issuable only as registered Certificates
without coupons in minimum denominations of [$100,000]* [$1,000]** Fractional
Undivided Interest and integral multiples of $1,000 in excess thereof except
that one Certificate may be in a different denomination. As provided in the
Agreement and subject to certain limitations therein set forth, the Certificates
are exchangeable for new Certificates of authorized denominations evidencing the
same aggregate Fractional Undivided Interest in the Trust, as requested by the
Certificateholder surrendering the same.

                  No service charge will be made for any such registration of
transfer or exchange, but the Trustee shall require payment by the Holder of a
sum sufficient to cover any tax or governmental charge payable in connection
therewith.

                  Each Certificateholder or Investor that is not a United States
person within the meaning of Section 7701(a)(30) of the Internal Revenue Code,
as amended, by its acceptance of a Certificate or a beneficial interest therein,
agrees to indemnify and hold harmless the Trust and the Trustee from and against
any improper failure to withhold taxes from amounts payable to it or for its
benefit. Each Certificateholder and Investor, by its acceptance of this
Certificate or a beneficial interest herein, agrees to treat the Trust as a
grantor trust for all U.S. federal, state and local income tax purposes.

                  The Trustee, the Registrar, and any agent of the Trustee or
the Registrar may treat the person in whose name this Certificate is registered
as the owner hereof for all purposes, and neither the Trustee, the Registrar,
nor any such agent shall be affected by any notice to the contrary.

                  The obligations and responsibilities created by the Agreement
and the Trust created thereby shall terminate upon the distribution to
Certificateholders of all amounts required

         *        To be included only on each Initial Certificate.

         **       To be included only on each Exchange Certificate.
<PAGE>   71
                                      A-7


to be distributed to them pursuant to the Agreement and the disposition of all
property held as part of the Trust Property.

                  UNTIL THE TRANSFER, THE AGREEMENT AND THIS CERTIFICATE SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
DELAWARE AND THE OBLIGATIONS, RIGHTS AND REMEDIES OF THE PARTIES HEREUNDER SHALL
BE DETERMINED IN ACCORDANCE WITH SUCH LAWS. FROM AND AFTER THE TRANSFER, THE
AGREEMENT AND THIS CERTIFICATE SHALL BE GOVERNED AND CONSTRUED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF NEW YORK AND THE OBLIGATIONS, RIGHTS AND REMEDIES
OF THE PARTIES HEREUNDER SHALL BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.
<PAGE>   72
                                      A-8


                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: October 6, 1998

                                         AMERICA WEST AIRLINES PASS THROUGH
                                           TRUST, SERIES 1998-1B-O

                                         By: WILMINGTON TRUST COMPANY,not in its
                                             individual capacity
                                             but solely as Trustee

                                         By: ___________________________________
                                             Name:
                                             Title:

[Attest:

----------------------
Authorized Signature]
<PAGE>   73
                                      A-9


              [FORM OF THE TRUSTEE'S CERTIFICATE OF AUTHENTICATION]

                    This is one of the Certificates referred
                      to in the within-mentioned Agreement.

                            WILMINGTON TRUST COMPANY,
                            not in its individual capacity but solely as Trustee

                            By: ________________________________________________
                                Authorized Officer
<PAGE>   74
                                      A-10


                             FORM OF TRANSFER NOTICE

                  FOR VALUE RECEIVED the undersigned registered holder hereby
sell(s), assign(s) and transfer(s) unto

Insert Taxpayer Identification No.

____________________

____________________

please print or typewrite name and address including zip code of assignee

____________________

the within Certificate and all rights thereunder, hereby irrevocably
constituting and appointing

____________________

attorney to transfer said Certificate on the books of the Trustee with full
power of substitution in the premises.

                     [THE FOLLOWING PROVISION TO BE INCLUDED
                               ON ALL CERTIFICATES
                         EXCEPT REGULATION S GLOBAL AND
                      REGULATION S DEFINITIVE CERTIFICATES]

                  In connection with any transfer of this Certificate occurring
prior to the date that is the earlier of the date of an effective Registration
Statement or the date two years after the later of the original issuance of this
Certificate or the last date on which this Certificate was held by America West
Airlines, Inc., the Trustee or any affiliate of such Persons, the undersigned
confirms that without utilizing any general solicitation or general advertising
that:

                                   [Check One]

[ ] (a) this Certificate is being transferred in compliance with the exemption
from registration under the Securities Act of 1933, as amended, provided by Rule
144A thereunder.

                                       or

[ ] (b) this Certificate is being transferred other than in accordance with (a)
above and documents are being furnished that comply with the conditions of
transfer set forth in this Certificate and the Agreement.

If neither of the foregoing boxes is checked, the Trustee or other Registrar
shall not be obligated to register this Certificate in the name of any Person
other than the Holder hereof unless and until the conditions to any such
transfer of registration set forth herein and in Section 3.06 of the Agreement
shall have been satisfied.
<PAGE>   75
                                      A-11

Date:__________________                              [Name of Transferor]

                                                     NOTE: The signature must
                                                     correspond with the name as
                                                     written upon the face of
                                                     the within-mentioned
                                                     instrument in every
                                                     particular, without
                                                     alteration or any change
                                                     whatsoever.

Signature Guarantee: ______________________

TO BE COMPLETED BY PURCHASER IF (a) ABOVE IS CHECKED.

                  The undersigned represents and warrants that it is purchasing
this Certificate for its own account or an account with respect to which it
exercises sole investment discretion and that it and any such account is a
"qualified institutional buyer" within the meaning of Rule 144A under the
Securities Act of 1933, as amended, and is aware that the sale to it is being
made in reliance on Rule 144A and acknowledges that it has received such
information regarding the Company as the undersigned has requested pursuant to
Rule 144A or has determined not to request such information and that it is aware
that the transferor is relying upon the undersigned's foregoing representations
in order to claim the exemption from registration provided by Rule 144A.

Dated:__________________           _____________________________
                                   NOTE: To be executed by an executive officer.
<PAGE>   76
                                                                       EXHIBIT B

             FORM OF CERTIFICATE TO BE DELIVERED IN CONNECTION WITH
               TRANSFERS OF CERTIFICATES PURSUANT TO REGULATION S

                                                                          [date]

Wilmington Trust Company
Rodney Square North
1100 North Market Street
Wilmington, DE  19890-0001

Attention:  Corporate Trust Trustee Administration

         Re:      America West Airlines Pass Through Trust (the "Trust"), Series
                  1998-1B-O, America West Airlines Pass Through Certificates,
                  Series 1998-1B-O (the "Certificates")

Sirs:

                  In connection with our proposed sale of $_____ Fractional
Undivided Interest of the Certificates, we confirm that such sale has been
effected pursuant to and in accordance with Regulation S under the Securities
Act of 1933, as amended, and, accordingly, we represent that:

                  (1) the offer of the Certificates was not made to a person in
         the United States or to or for the account or benefit of a U.S. person;

                  (2) either (a) at the time the buy order was originated, the
         transferee was outside the United States or we and any person acting on
         our behalf reasonably believed that the transferee was outside the
         United States or (b) the transaction was executed in, on or through the
         facilities of a designated off-shore securities market and neither we
         nor any person acting on our behalf knows that the transaction has been
         pre-arranged with a buyer in the United States;

                  (3) no directed selling efforts have been made in the United
         States in contravention of the requirements of Rule 903(a) or Rule
         904(a) of Regulation S, as applicable; and

                  (4) the transaction is not part of a plan or scheme to evade
         the registration requirements of the Securities Act.

                  In addition, if the sale is made during a restricted period
and the provisions of Rule 903(b)(2) or Rule 904(b)(1) of Regulation S are
applicable thereto, we confirm that such sale has been made in accordance with
the applicable provisions of Rule 903(b)(2) or Rule 904(b)(1), as the case may
be.

                  You and America West Airlines, Inc. are entitled to rely upon
this letter and are irrevocably authorized to produce this letter or a copy
hereof to any interested party in any
<PAGE>   77
                                       B-2


administrative or legal proceedings or official inquiry with respect to the
matters covered hereby. Terms used in this certificate have the meanings set
forth in Regulation S.

                                                     Very truly yours,

                                                     [Name of Transferor]
<PAGE>   78
                                                                       EXHIBIT C

                FORM OF CERTIFICATE TO BE DELIVERED IN CONNECTION
                        WITH TRANSFERS OF CERTIFICATES TO
                   NON-QIB INSTITUTIONAL ACCREDITED INVESTORS

                                                      [date]

Wilmington Trust Company
Rodney Square North
1100 North Market Street
Wilmington, DE  19890-0001

Attention:  Corporate Trust Trustee Administration

America West Airlines, Inc.
4000 East Sky Harbor Boulevard
Phoenix, Arizona 85043

                              AMERICA WEST AIRLINES
               PASS THROUGH TRUST, SERIES 1998-1B-O (the "Trust")
                   Pass Through Certificates, Series 1998-1B-O
                              (the "Certificates")

Ladies and Gentlemen:

         In connection with our proposed purchase of U.S. $[_____________]
Fractional Undivided Interest of Certificates, we confirm that:

         1. We understand that any subsequent transfer of the Certificates is
subject to certain restrictions and conditions set forth in the Pass Through
Trust Agreement, dated as of October 6, 1998, between America West Airlines,
Inc. (the "Company") and Wilmington Trust Company (the "Trustee") relating to
the Certificates, and we agree to be bound by, and not to resell, pledge or
otherwise transfer the Certificates except in compliance with, such restrictions
and conditions and the Securities Act of 1933, as amended (the "Securities
Act").

         2. We are purchasing Certificates having an aggregate principal amount
of not less than $100,000 and each account (if any) for which we are purchasing
Certificates is purchasing Certificates having an aggregate principal amount of
not less than $100,000.

         3. We understand that the Certificates have not been registered under
the Securities Act, that the Certificates are being sold to us in a transaction
that is exempt from the registration requirements of the Securities Act and that
the Certificates may not be offered or resold except as permitted in the
following sentence. We agree, on our own behalf and on behalf of any accounts
for which we are acting as hereinafter stated, that, if we should sell any
Certificates within two
<PAGE>   79
                                       C-2


years after the later of the original issuance of such Certificate and the last
date on which such Certificate is owned by the Company, the Trustee or any
affiliate of any of such persons, we will do so only (A) to the Company, (B) in
accordance with Rule 144A under the Securities Act to a "qualified institutional
buyer" (as defined therein), (C) outside the United States in accordance with
Rule 904 of Regulation S under the Securities Act, (D) pursuant to the exemption
from registration provided by Rule 144 under the Securities Act or (E) pursuant
to an effective registration statement under the Securities Act, and we further
agree to provide to any person purchasing any of the Certificates from us a
notice advising such purchaser that resales of the Certificates are restricted
as stated herein.

         4. We understand that, on any proposed resale of any Certificates, we
will be required to furnish to the Company and the Trustee such certifications,
legal opinions and other information as the Company and the Trustee may
reasonably require to confirm that the proposed sale complies with the foregoing
restrictions. We further understand that the Certificates purchased by us will
bear a legend to the foregoing effect.

         5. We are an institutional "accredited investor" (as defined in Rule
501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and have
such knowledge and experience in financial and business matters as to be capable
of evaluating the merits and risks of our investment in the Certificates, and we
and any accounts for which we are acting are each able to bear the economic risk
of our or their investments.

         6. We are acquiring the Certificates purchased by us for our own
account or for one or more accounts (each of which is an institutional
"accredited investor") as to each of which we exercise sole investment
discretion and not with a view to any distribution of the Certificates, subject,
nevertheless to the understanding that the disposition of our property shall at
all times be and remain within our control.

                  You are entitled to rely upon this letter and are irrevocably
authorized to produce this letter or a copy thereof to any interested party in
any administrative or legal proceedings or official inquiry with respect to the
matters covered hereby.

                                                     Very truly yours,

                                                     By: _______________________
                                                         Name:
                                                         Title:
<PAGE>   80
                                                                       EXHIBIT D

                   FORM OF ASSIGNMENT AND ASSUMPTION AGREEMENT
            America West Airlines Pass Through Trust, Series 1998-1B

                  ASSIGNMENT AND ASSUMPTION AGREEMENT, dated ____________, 199_
(the "Agreement"), between Wilmington Trust Company, a Delaware banking
corporation ("WTC"), not in its individual capacity except as expressly provided
herein, but solely as trustee under the Pass Through Trust Agreement dated as of
October 6, 1998 (as amended, modified or otherwise supplemented from time to
time, the "Pass Through Trust Agreement") in respect of the America West
Airlines Pass Through Trust, Series 1998-1B-O (the "Assignor"), and Wilmington
Trust Company, a Delaware banking corporation, not in its individual capacity
except as expressly provided herein, but solely as trustee under the Pass
Through Trust Agreement dated as of October 6, 1998 (the "New Pass Through Trust
Agreement") in respect of the America West Airlines Pass Through Trust, Series
1998-1B-S (the "Assignee").

                              W I T N E S S E T H:

                  WHEREAS, the parties hereto desire to effect on the date
hereof (the "Transfer Date") (a) the transfer by the Assignor to the Assignee of
all of the right, title and interest of the Assignor in, under and with respect
to, among other things, the Trust Property and each of the documents listed in
Schedule I hereto (the "Scheduled Documents") and (b) the assumption by the
Assignee of the obligations of the Assignor (i) under the Scheduled Documents
and (ii) in respect of the Certificates issued under the Pass Through Trust
Agreement; and

                  WHEREAS, the Scheduled Documents permit such transfer upon
satisfaction of certain conditions heretofore or concurrently herewith being
complied with;

                  NOW, THEREFORE, in consideration of the premises and of the
mutual covenants and agreements herein contained, the parties hereto do hereby
agree as follows (capitalized terms used herein without definition having the
meaning ascribed thereto in the Pass Through Trust Agreement):

                  1. Assignment. The Assignor does hereby sell, assign, convey,
transfer and set over unto the Assignee as of the Transfer Date all of its
present and future right, title and interest in, under and with respect to the
Trust Property and the Scheduled Documents and each other contract, agreement,
document or instrument relating to the Trust Property or the Scheduled Documents
(such other contracts, agreements, documents or instruments, together with the
Scheduled Documents, to be referred to as the "Assigned Documents"), and any
proceeds therefrom, together with all documents and instruments evidencing any
of such right, title and interest.

                  2. Assumption. The Assignee hereby assumes for the benefit of
the Assignor and each of the parties listed in Schedule II hereto (collectively,
the "Beneficiaries") all of the duties and obligations of the Assignor, whenever
accrued, pursuant to the Assigned Documents and hereby confirms that it shall be
deemed a party to each of the Assigned Documents to which the Assignor is a
party and shall be bound by all the terms thereof (including the agreements and
obligations of the Assignor set forth therein) as if therein named as the
Assignor. Further, the Assignee hereby assumes for the benefit of the Assignor
and the Beneficiaries all of the duties
<PAGE>   81
                                       D-2


and obligations of the Assignor under the Outstanding Certificates and hereby
confirms that the Certificates representing Fractional Undivided Interests under
the Pass Through Trust Agreement shall be deemed for all purposes of the Pass
Through Trust Agreement and the New Pass Through Trust Agreement to be
certificates representing the same fractional undivided interests under the New
Pass Through Trust Agreement equal to their respective beneficial interests in
the trust created under the Pass Through Trust Agreement.

                  3. Effectiveness. This Agreement shall be effective upon the
execution and delivery hereof by the parties hereto, and each Certificateholder,
by its acceptance of its Certificate or a beneficial interest therein, agrees to
be bound by the terms of this Agreement.

                  4. Payments. The Assignor hereby covenants and agrees to pay
over to the Assignee, if and when received following the Transfer Date, any
amounts (including any sums payable as interest in respect thereof) paid to or
for the benefit of the Assignor that, under Section 1 hereof, belong to the
Assignee.

                  5. Further Assurances. The Assignor shall, at any time and
from time to time, upon the request of the Assignee, promptly and duly execute
and deliver any and all such further instruments and documents and take such
further action as the Assignee may reasonably request to obtain the full
benefits of this Agreement and of the right and powers herein granted. The
Assignor agrees to deliver the Global Certificates, and all Trust Property, if
any, then in the physical possession of the Assignor, to the Assignee.

                  6. Representations and Warranties. (a) The Assignee represents
and warrants to the Assignor and each of the Beneficiaries that:

                  (i) it has all requisite power and authority and legal right
         to enter into and carry out the transactions contemplated hereby and to
         carry out and perform the obligations of the "Pass Through Trustee"
         under the Assigned Documents;

                  (ii) on and as of the date hereof, the representations and
         warranties of the Assignee set forth in Section 7.15 of the New Pass
         Through Trust Agreement are true and correct.

                  (b) The Assignor represents and warrants to the Assignee that:

                  (i) it is duly incorporated, validly existing and in good
         standing under the laws of the State of Delaware and has the full trust
         power, authority and legal right under the laws of the State of
         Delaware and the United States pertaining to its trust and fiduciary
         powers to execute and deliver this Agreement;

                  (ii) the execution and delivery by it of this Agreement and
         the performance by it of its obligations hereunder have been duly
         authorized by it and will not violate its articles of association or
         by-laws or the provisions of any indenture, mortgage, contract or other
         agreement to which it is a party or by which it is bound; and

                  (iii) this Agreement constitutes the legal, valid and binding
         obligations of it enforceable against it in accordance with its terms,
         except as the same may be limited by applicable bankruptcy, insolvency,
         reorganization, moratorium or similar laws affecting
<PAGE>   82
                                       D-3


         the rights of creditors generally and by general principles of equity,
         whether considered in a proceeding at law or in equity.

                  7. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAW OF THE STATE OF NEW YORK INCLUDING MATTERS
OF CONSTRUCTION, VALIDITY AND PERFORMANCE, WITHOUT GIVING EFFECT TO PRINCIPLES
OF CONFLICTS OF LAWS.

                  8. Counterparts. This Agreement may be executed in any number
of counterparts, all of which together shall constitute a single instrument. It
shall not be necessary that any counterpart be signed by both parties so long as
each party shall sign at least one counterpart.

                  9. Third Party Beneficiaries. The Assignee hereby agrees, for
the benefit of the Beneficiaries, that its representations, warranties and
covenants contained herein are also intended to be for the benefit of each
Beneficiary, and each Beneficiary shall be deemed to be an express third party
beneficiary with respect thereto, entitled to enforce directly and in its own
name any rights or claims it may have against such party as such beneficiary.

                  IN WITNESS WHEREOF, the parties hereto, through their
respective officers thereunto duly authorized, have duly executed this
Assignment as of the day and year first above written.

                                    ASSIGNOR:

                                    WILMINGTON TRUST COMPANY, not in its
                                    individual capacity except as expressly
                                    provided herein, but solely as trustee under
                                    the Pass Through Trust Agreement in respect
                                    of the America West Airlines Pass Through
                                    Trust 1998-1B-O

                                    By: ________________________________________
                                        Title:

                                    ASSIGNEE:

                                    WILMINGTON TRUST COMPANY, not in its
                                    individual capacity except as expressly
                                    provided herein, but solely as trustee under
                                    the Pass Through Trust Agreement in respect
                                    of the America West Airlines Pass Through
                                    Trust 1998-1B-S

                                    By: ________________________________________
                                        Title:
<PAGE>   83
                                                                      Schedule I

                         Schedule of Assigned Documents

(1)      Intercreditor Agreement dated as of October 6, 1998 among the Trustee,
         the Other Trustees, the Liquidity Provider, the liquidity provider, if
         any, relating to the Certificates issued under (and as defined in) each
         of the Other Pass Through Trust Agreements and the Subordination Agent.

(2)      Registration Rights Agreement dated as of October 6, 1998 among the
         Initial Purchasers, the Trustee, the Other Trustees, and the Company.

(3)      Escrow and Paying Agent Agreement (Class A) dated as of October 6, 1998
         among the Escrow Agent, the Initial Purchasers, the Trustee and the
         Paying Agent.

(4)      Note Purchase Agreement dated as of October 6, 1998 among the Company,
         the Trustee, the Other Trustees, the Depositary, the Escrow Agent, the
         Paying Agent and the Subordination Agent.

(5)      Deposit Agreement (Class A) dated as of October 6, 1998 between the
         Escrow Agent and the Depositary.

(6)      Each of the Operative Agreements (as defined in the Participation
         Agreement for each Aircraft) in effect as of the Transfer Date.
<PAGE>   84
                                                                     Schedule II

                            Schedule of Beneficiaries

Wilmington Trust Company, not in its individual capacity but solely as
Subordination Agent.

Wilmington Trust Company, not in its individual capacity but solely as Paying
Agent

ABN AMRO Bank, N.V., acting through its Chicago branch, as Liquidity Provider

America West Airlines, Inc.

Morgan Stanley & Co. Incorporated, as Initial Purchaser

Donaldson, Lufkin & Jenrette Securities Corporation, as Initial Purchaser

Merrill Lynch, Pierce, Fenner & Smith Incorporated, as Initial Purchaser

Salomon Smith Barney Inc., as Initial Purchaser

Wilmington Trust Company, as Escrow Agent

Each of the other parties to the Assigned Documents
<PAGE>   85
                                                                       EXHIBIT E

            FORM OF NOTICE TO DESIGNATE NOMINEE AS WITHHOLDING AGENT
          (Treas. Reg. Section 1.1445-8(f); 17 C.F.R. 240.10b-17(b)(1))

                                                                          [DATE]

National Association of
Securities Dealers, Inc.
Market Operations
80 Merritt Blvd.
Trumbull, CT  06611

         Re:      America West Airlines Pass Through Trust, Series 1998-1B-O
                  Pass Through Certificates, Series 1998-1B-O

                  With respect to distributions to be made on [INSERT
DISTRIBUTION DATE] to holders of the above-referenced Pass Through Certificates
in the amount of $ ____ per $1,000 principal amount of Certificate, we hereby
designate the appropriate nominees to withhold from amounts distributable to any
non-U.S. Person such amounts as required by Section 1446 of the Internal Revenue
Code of 1986, as amended. The term "non-U.S. Person" means any person or entity
that, for U.S. federal income tax purposes, is not a "U.S. Person." "U.S.
Person" for this purpose means a citizen or resident of the United States, a
corporation, partnership or other entity created or organized under the laws of
the United States or any political subdivision thereof, or an estate or trust,
the income of which is subject to U.S. federal income taxation regardless of its
source. The date of record for determining holders of Certificates entitled to
receive the distribution on [INSERT DISTRIBUTION DATE] is [INSERT RELATED RECORD
DATE].

                                                      Very truly yours,