<PAGE>   1
                                                                     Exhibit 4.8
--------------------------------------------------------------------------------




                          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 1998-1C-O

            7.84% Initial Pass Through Certificates, Series 1998-1C-O
           7.84% Exchange Pass Through Certificates, Series 1998-1C-O




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<PAGE>   2
Reconciliation and tie between America West Airlines Pass Through Trust
Agreement, Series 1998-1C-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.

<TABLE>
<CAPTION>
        Trust Indenture Act                       Pass Through Trust
         of 1939 Section                          Agreement Section
         ---------------                          -----------------
<S>                                               <C>
            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
</TABLE>
<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 ..........     35
</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 ...........................................................     37

ARTICLE VII  THE TRUSTEE ...........................................................................     38
      Section 7.01.  Certain Duties and Responsibilities ...........................................     38
      Section 7.02.  Notice of Defaults ............................................................     38
      Section 7.03.  Certain Rights of Trustee .....................................................     38
      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 .......................................     41
      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 ...................     43
      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 .....................................     45
      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 .....................................     47
      Section 8.01.  The Company to Furnish Trustee with Names and Addresses of Certificateholders..     47
      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 .....................................     51
      Section 9.04.  Execution of Supplemental Agreements ..........................................     51
      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 ..................................     55
      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 .....................................................     57
      Section 12.09.  Benefits of Agreement ......................................................     57
      Section 12.10.  Legal Holidays .............................................................     57
      Section 12.11.  Counterparts ...............................................................     57
      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 1998-1C-O and the issuance of
7.84% America West Airlines Pass Through Trust, Series 1998-1C-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 January 2, 2012.

            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 1998-1B-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 1998-1B-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 America West Airlines Pass Through Trust, Series
      1998-1C-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
      1998-1C-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 equaling
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 "7.84% Initial
Pass Through Certificates, Series 1998-1C-O" and the Exchange Certificates shall
be known as the "7.84% Exchange Pass Through
<PAGE>   23
                                      -18-


Certificates, Series 1998-1C-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 $17,705,000.

            (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 equaling 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.


                                   ARTICLE IV
<PAGE>   34
                                      -29-


                         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 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
<PAGE>   35
                                      -30-


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
the information provided by the Escrow Paying Agent under the Escrow Agreement).
Such
<PAGE>   36
                                      -31-


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 for such Regular Distribution Dates and (z)
the expected principal distribution schedule of the
<PAGE>   37
                                      -32-


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 Person
      of the due and punctual performance and observance of each covenant and
<PAGE>   38
                                      -33-


      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 (which shall not expire upon any
      purchase of the Class A Certificates pursuant to the Class B Trust
      Agreement) to purchase, for the purchase prices set forth in the Class A
      Trust Agreement and the Class B Trust Agreement, respectively, all, but
      not less than all, of the Class A Certificates and the Class B
      Certificates upon ten days' written notice to the Class A Trustee, the
      Class B 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 and the
      Class B 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 and the Class B
      Certificates pursuant to this Section 6.01(b); and
<PAGE>   39
                                      -34-


            (ii) by acceptance of its Certificate, each Certificateholder agrees
      that at any time after the occurrence and during the continuation of a
      Triggering Event, each Class D Certificateholder shall have the right
      (which shall not expire upon any purchase of the Class A Certificates
      pursuant to the Class B Trust Agreement or any purchase of the Class A
      Certificates and the Class B Certificates pursuant to clause (b)(i) above)
      to purchase all, but not less than all, of the Class A Certificates, the
      Class B Certificates and the Certificates upon ten days' written notice to
      the Class A Trustee, the Class B Trustee, the Trustee and each other Class
      D Certificateholder, provided that (A) 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 Class B
      Certificates and the 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 (B) 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 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 Class B
Certificates and the 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 D Certificateholder(s), 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
<PAGE>   40
                                      -35-


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 B Certificate", "Class B Certificateholder", "Class B Trust",
"Class B Trust Agreement", "Class B 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.

            (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
<PAGE>   41
                                      -36-


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 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.
<PAGE>   42
                                      -37-


            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

            (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
<PAGE>   43
                                      -38-


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.

            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:
<PAGE>   44
                                      -39-


            (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;

            (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.
<PAGE>   45
                                      -40-


            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 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,
<PAGE>   46
                                      -41-


      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.

            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.
<PAGE>   47
                                      -42-


            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;

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
<PAGE>   48
                                      -43-


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.

            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.
<PAGE>   49
                                      -44-


            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.

            (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
<PAGE>   50
                                      -45-


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.

            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
<PAGE>   51
                                      -46-


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 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
<PAGE>   52
                                      -47-


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 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.
<PAGE>   53
                                      -48-


            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;

            (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,
<PAGE>   54
                                      -49-


      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

            (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
<PAGE>   55
                                      -50-


      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 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;
<PAGE>   56
                                      -51-


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

            (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
<PAGE>   57
                                      -52-


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, 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
<PAGE>   58
                                      -53-


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
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
<PAGE>   59
                                      -54-


                  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
      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
<PAGE>   60
                                      -55-


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 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.
<PAGE>   61
                                      -56-


            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

            (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.
<PAGE>   62
                                      -57-


            (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.

            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
<PAGE>   63
                                      -58-


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 1998-1C-O

                7.84% America West Airlines [Initial] [Exchange]
                            Pass Through Certificate,
                                Series 1998-1C-O

                 Final Legal Distribution Date: January 2, 2012

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
            0.0056481220% 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 1998-1C-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 "7.84%
America West Airlines [Initial] [Exchange] Pass Through Certificates, Series
1998-1C-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 1998-1C-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 1998-1C-O, America West Airlines Pass Through
            Certificates, Series 1998-1C-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 1998-1C-O (the "Trust")
                   Pass Through Certificates, Series 1998-1C-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 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
<PAGE>   79
                                      C-2


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 1998-1C


            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 1998-1C-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 1998-1C-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 1998-1C-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 1998-1C-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 1998-1C-O
            Pass Through Certificates, Series 1998-1C-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,