<PAGE>   1
                                                                    Exhibit 4.16





                             NOTE PURCHASE AGREEMENT

                         Dated as of September 21, 1999

                                      Among

                          AMERICA WEST AIRLINES, INC.,

                            WILMINGTON TRUST COMPANY,
                    as Pass Through Trustee under each of the
                          Pass Through Trust Agreements

                            WILMINGTON TRUST COMPANY,
                             as Subordination Agent

                            WILMINGTON TRUST COMPANY,
                                 as Escrow Agent

                                       and

                            WILMINGTON TRUST COMPANY,
                                 as Paying Agent
<PAGE>   2
                        INDEX TO NOTE PURCHASE AGREEMENT
<TABLE>
<CAPTION>
                                                                                                               Page
                                                                                                               ----
<S>                                                                                                            <C>
SECTION 1.  Financing of Aircraft.................................................................................2

SECTION 2.  Conditions Precedent..................................................................................8

SECTION 3.  Representations and Warranties........................................................................8

SECTION 4.  Covenants ...........................................................................................12

SECTION 5.  Notices .............................................................................................14

SECTION 6.  Expenses ............................................................................................15

SECTION 7.  Further Assurances...................................................................................16

SECTION 8.  Miscellaneous........................................................................................16

SECTION 9.  Governing Law........................................................................................17
</TABLE>



<TABLE>
<CAPTION>
                                          Schedules

<S>                        <C>
Schedule I                 Aircraft and Scheduled Delivery Months
Schedule II                Pass Through Trust Agreements
Schedule III               Deposit Agreements
Schedule IV                Escrow and Paying Agent Agreements
Schedule V                 Mandatory Document Terms
Schedule VI                Mandatory Economic Terms
Schedule VII               Aggregate Amortization Schedule


                                           Annex

Annex A                    Definitions


                                          Exhibits

Exhibit A-1                Form of Leased Aircraft Participation Agreement
Exhibit A-2                Form of Lease
Exhibit A-3                Form of Leased Aircraft Indenture
Exhibit A-4                Form of Aircraft Purchase Agreement Assignment
Exhibit A-5                Form of Leased Aircraft Trust Agreement
Exhibit B                  Form of Delivery Notice
</TABLE>

                                      -i-
<PAGE>   3
<TABLE>
<CAPTION>
<S>                        <C>
Exhibit C-1                Form of Owned Aircraft Participation Agreement
Exhibit C-2                Form of Owned Aircraft Indenture
Exhibit D                  Additional Subordination Provision for Series D Equipment Notes
</TABLE>

                                      -ii-
<PAGE>   4
                             NOTE PURCHASE AGREEMENT

                  This NOTE PURCHASE AGREEMENT, dated as of September 21, 1999,
among (i) AMERICA WEST AIRLINES, INC., a Delaware corporation (the "Company"),
(ii) WILMINGTON TRUST COMPANY ("WTC"), a Delaware banking corporation, not in
its individual capacity except as otherwise expressly provided herein, but
solely as trustee (in such capacity together with its successors in such
capacity, the "Pass Through Trustee") under each of the three separate Pass
Through Trust Agreements (as defined below), (iii) WILMINGTON TRUST COMPANY, a
Delaware banking corporation, as subordination agent and trustee (in such
capacity together with its successors in such capacity, the "Subordination
Agent") under the Intercreditor Agreement (as defined below), (iv) WILMINGTON
TRUST COMPANY, a Delaware banking corporation, as Escrow Agent (in such capacity
together with its successors in such capacity, the "Escrow Agent"), under each
of the Escrow and Paying Agent Agreements (as defined below) and (v) WILMINGTON
TRUST COMPANY, a Delaware banking corporation, as Paying Agent (in such capacity
together with its successors in such capacity, the "Paying Agent") under each of
the Escrow and Paying Agent Agreements.

                              W I T N E S S E T H:

                  WHEREAS, capitalized terms used but not defined herein shall
have the meanings ascribed to such terms in Annex A hereto;

                  WHEREAS, the Company has obtained commitments from the
Manufacturer pursuant to the Aircraft Purchase Agreement for the delivery of the
ten aircraft listed on Schedule I hereto (together with any aircraft substituted
therefor in accordance with the Aircraft Purchase Agreement prior to the
delivery thereof, the "Aircraft");

                  WHEREAS, pursuant to each of the Pass Through Trust Agreements
set forth in Schedule II hereto, and concurrently with the execution and
delivery of this Agreement, separate grantor trusts (collectively, the "Pass
Through Trusts" and, individually, a "Pass Through Trust") have been created to
facilitate certain of the transactions contemplated hereby, including, without
limitation, the issuance and sale of pass through certificates pursuant thereto
(collectively, the "Certificates") to provide for a portion of the financing of
the Aircraft;

                  WHEREAS, the Company has entered into the Purchase Agreement
dated as of September 14, 1999 (the "Purchase Agreement") with the several
initial purchasers (the "Initial Purchasers") named therein, which provides that
the Company will cause each Pass Through Trustee to issue and sell the
Certificates to the Initial Purchasers;

                  WHEREAS, concurrently with the execution and delivery of this
Agreement, (i) the Escrow Agents and the Depositary entered into the Deposit
Agreements set forth in Schedule III hereto (the "Initial Deposit Agreements")
whereby the applicable Escrow Agent agreed to direct the Initial Purchasers to
make certain deposits referred to therein on the Issuance Date (the "Initial
Deposits") and to permit the applicable Pass Through Trustee to make additional
deposits from time to time thereafter (the Initial Deposits together with such
additional deposits are collectively referred to as the "Deposits") and (ii) the
Pass Through Trustees, the Initial Purchasers, the Paying Agents and the Escrow
Agents entered into the Escrow and Paying Agent
<PAGE>   5
                                                                               2

Agreements set forth in Schedule IV hereto (the "Escrow and Paying Agent
Agreements") whereby, among other things, (a) the Initial Purchasers agreed to
deliver an amount equal to the amount of the Initial Deposits to the Depositary
on behalf of the applicable Escrow Agent and (b) the applicable Escrow Agent,
upon the Depositary receiving such amount, has agreed to deliver escrow receipts
to be affixed to each Certificate;

                  WHEREAS, prior to (or, in the case of the utilization of
bridge financing, after) the delivery of each Aircraft from the Manufacturer,
the Company will determine whether to enter into a leveraged lease transaction
as lessee with respect to such Aircraft (a "Leased Aircraft") or to purchase as
owner such Aircraft (an "Owned Aircraft") and will give to the Pass Through
Trustee a Delivery Notice (as defined below) specifying its election;

                  WHEREAS, upon receipt of a Delivery Notice with respect to an
Aircraft, subject to the terms and conditions of this Agreement, the applicable
Pass Through Trustees will enter into the applicable Financing Agreements
relating to such Aircraft;

                  WHEREAS, upon the delivery of each Aircraft, each Pass Through
Trustee will fund its purchase of Equipment Notes with the proceeds of one or
more Deposits withdrawn by the applicable Escrow Agent under the related Deposit
Agreement bearing the same interest rate as the Certificates issued by such Pass
Through Trust;

                  WHEREAS, concurrently with the execution and delivery of this
Agreement, (i) Morgan Stanley Capital Services, Inc., a Delaware corporation
(the "Liquidity Provider"), has entered into two revolving credit agreements
(each, a "Liquidity Facility"), one each for the benefit of the
Certificateholders of each Pass Through Trust, with the Subordination Agent, as
agent for the Pass Through Trustee on behalf of each such Pass Through Trust and
(ii) the Pass Through Trustee, the Liquidity Provider, the Policy Provider (as
defined below) and the Subordination Agent have entered into the Intercreditor
Agreement, dated as of the date hereof (the "Intercreditor Agreement"); and

                  WHEREAS, concurrently with the execution and delivery of this
Agreement Ambac Assurance Corporation (the "Policy Provider") has entered into
the Insurance and Indemnity Agreement (the "Policy Provider Agreement"), with
the Company and the Subordination Agent, as agent and trustee for the Pass
Through Trustee of the Class G Trust on behalf of the Class G Trust, and the
Policy Provider has issued the certificate guaranty insurance policy (the
"Policy") provided for therein for the benefit of the Class G
Certificateholders.

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

                  SECTION 1. Financing of Aircraft. (a) The Company confirms
that it has entered into the Aircraft Purchase Agreement with the Manufacturer
pursuant to which the Company has agreed to purchase, and the Manufacturer has
agreed to deliver, the Aircraft in the months specified in Schedule I hereto,
all on and subject to terms and conditions specified in the Aircraft Purchase
Agreement. The Company agrees to finance the Aircraft in the manner
<PAGE>   6
                                                                               3

provided herein, all on and subject to the terms and conditions hereof and of
the relevant Financing Agreements.

                  (b) In furtherance of the foregoing, the Company agrees to
give the parties hereto, the Depositary, the Policy Provider and each of the
Rating Agencies not less than two Business Days' prior written notice in the
form of the notice set out in Exhibit B hereto (a "Delivery Notice") of the
scheduled delivery date (the "Scheduled Delivery Date") (or, in the case of a
substitute Delivery Notice under Section 1(e) or (f) hereof, one Business Day's
prior notice) in respect of each Aircraft under the Aircraft Purchase Agreement,
or in the case of the utilization of bridge financing as contemplated by Section
1(e) hereof in respect of any Aircraft, one Business Day's prior notice of the
date of the financing of such Aircraft pursuant to the relevant Financing
Agreements, which notice shall:

                  (i) specify whether the Company has elected to treat such
         Aircraft as a Leased Aircraft or an Owned Aircraft;

                  (ii) specify the Scheduled Delivery Date of such Aircraft
         (which shall be a Business Day before the Cut-off Date and, except as
         provided in Section 1(f) hereof, the date (the "Funding Date") on which
         the financing therefor in the manner provided herein shall be
         consummated);

                  (iii) instruct the Pass Through Trustee to execute and deliver
         to the relevant Escrow Agent a withdrawal certificate in the form of
         Exhibit B to the Escrow Agent so as to provide a Notice of Purchase
         Withdrawal to the Depositary with respect to the Equipment Notes to be
         issued in connection with the financing of such Aircraft;

                  (iv) instruct the Pass Through Trustee to enter into the
         Participation Agreement included in the Financing Agreements with
         respect to such Aircraft in such form and at such a time on or before
         the Funding Date specified in such Delivery Notice and to perform its
         obligations thereunder;

                  (v) specify the aggregate principal amount of each series of
         Equipment Notes to be issued, and purchased by the Pass Through
         Trustees, in connection with the financing of such Aircraft scheduled
         to be delivered on such Funding Date (which shall in all respects
         comply with the Mandatory Economic Terms); and

                  (vi) if such Aircraft is to be a Leased Aircraft, certify that
         the related Owner Participant (A) is not an Affiliate of the Company
         and (B) based on the representations of such Owner Participant, is
         either (1) a Qualified Owner Participant or (2) any other person the
         obligations of which under the Owner Participant Agreements (as defined
         in the applicable Participation Agreement) are guaranteed by a
         Qualified Owner Participant.

Notwithstanding the foregoing, (i) in the event the date of issuance of the
Certificates coincides with the Scheduled Delivery Date of any Aircraft to be
financed pursuant to the terms hereof, the Delivery Notice therefor may be
delivered to the parties hereto on such Scheduled Delivery Date and (ii) the
Delivery Notice shall be modified in the case of a Special Structure as
described in Section 1(c) below.
<PAGE>   7
                                                                               4

                  (c) Upon receipt of a Delivery Notice, the Pass Through
Trustees shall, and shall cause the Subordination Agent to, enter into and
perform their obligations under the Participation Agreement and other
instructions specified in such Delivery Notice, provided that such Participation
Agreement and the other Lease Financing Agreements or Owner Financing Agreements
to be entered into pursuant to such Participation Agreement shall be in the
forms thereof annexed hereto in all material respects with such changes therein
as shall have been requested by the related Owner Participant (in the case of
Lease Financing Agreements) or by the initial purchasers of the Series D
Equipment Notes or Class D Certificates (as defined in the Intercreditor
Agreement), agreed to by the Company and, if modified in any material respect,
as to which prior written consent of the Policy Provider shall have been
obtained and as to which Rating Agency Confirmation shall have been obtained
from each Rating Agency by the Company (to be delivered by the Company to the
applicable Pass Through Trustee on or before the relevant Delivery Date, it
being understood that if Policy Provider consent and Rating Agency Confirmation
shall have been received with respect to any Financing Agreements and such
Financing Agreements are utilized for subsequent Aircraft (or Substitute
Aircraft) without material modifications, no additional Policy Provider consent
or Rating Agency Confirmation shall be required); provided, however, that the
relevant Financing Agreements as executed and delivered shall not vary the
Mandatory Economic Terms and shall contain the Mandatory Document Terms.
Notwithstanding the foregoing, (i) if the Company elects to structure the
financing of a New Aircraft in a way other than contemplated by the forms of
Financing Agreements annexed to this Agreement (a "Special Structure"), it shall
specify in the Delivery Notice that the forms of financing agreements to be
entered into by the Applicable Pass Through Trustees and Subordination Agent
shall be furnished by the Company on the Funding Date, provided that (x) such
financing agreements shall not vary the Mandatory Economic Terms, (y) the
Company shall furnish to each applicable Pass Through Trustee a Rating Agency
Confirmation from each Rating Agency on or prior to the relevant Funding Date
and (z) the Company shall have obtained the prior written consent of the Policy
Provider to such Special Structure, and (ii) an Indenture may be modified to the
extent required pursuant to Section 4(a)(vi) of this Agreement. The Company
shall pay the reasonable costs and expenses of the Rating Agencies in connection
with obtaining any such Rating Agency Confirmation. With respect to each
Aircraft (except in the case of a Special Structure), the Company shall cause
WTC (or such other person that meets the eligibility requirements to act as
mortgagee under the Leased Aircraft Indenture or Owned Aircraft Indenture) shall
execute as Loan Trustee the Financing Agreements relating to such Aircraft to
which such Loan Trustee is intended to be a party, and the Company shall
concurrently therewith execute such Financing Agreements to which the Company is
intended to be a party and perform its respective obligations thereunder. Upon
the request of the Policy Provider or of either Rating Agency, the Company shall
deliver or cause to be delivered to such Rating Agency a true and complete copy
of each Financing Agreement (or, in the case of a Special Structure, each
financing agreement) relating to the financing of each Aircraft together with a
true and complete set of the closing documentation (including legal opinions)
delivered to the related Loan Trustee, Subordination Agent and Pass Through
Trustee under the related Participation Agreement.

                  (d) If after giving any Delivery Notice, there shall be a
delay in the delivery of an Aircraft, or if on the Scheduled Delivery Date of an
Aircraft the financing thereof in the manner contemplated hereby shall not be
consummated for whatever reason, the Company shall give the parties hereto and
the Policy Provider prompt notice thereof. Concurrently with the
<PAGE>   8
                                                                               5

giving of such notice of postponement or subsequently, the Company shall give
the parties hereto and the Policy Provider a substitute Delivery Notice
specifying the date to which such delivery and related financing shall have been
re-scheduled (which shall be a Business Day before the Cut-off Date on which the
Escrow Agents shall be entitled to withdraw one or more Deposits under each of
the applicable Deposit Agreements to enable each applicable Pass Through Trustee
to fund its purchase of the related Equipment Notes). Upon receipt of any such
notice of postponement, each applicable Pass Through Trustee shall comply with
its obligations under Section 7.01 of each of the Pass Through Trust Agreements
and thereafter the financing of the relevant Aircraft shall take place on the
re-scheduled Delivery Date therefor (all on and subject to the terms and
conditions of the relevant Financing Agreements or other financing agreements in
the case of a Special Structure) unless further postponed as provided herein.

                  (e) Anything in this Section 1 to the contrary
notwithstanding, the Company shall have the right at any time on or before the
Scheduled Delivery Date of any Aircraft, and subsequent to its giving a Delivery
Notice therefor, to postpone the Scheduled Delivery Date of such Aircraft so as
to enable the Company to change its election to treat such Aircraft as a Leased
Aircraft or an Owned Aircraft by written notice of such postponement to the
other parties hereto. The Company shall subsequently give the parties hereto a
substitute Delivery Notice complying with the provisions of Section 1(b) hereof
and specifying the new Funding Date for such postponed Aircraft (which shall be
a Business Day occurring before the Cut-off Date and on which the Escrow Agents
shall be entitled to withdraw Deposits under each of the applicable Deposit
Agreements sufficient to enable each applicable Pass Through Trustee to fund its
purchase of the related Equipment Notes). In addition, the Company shall have
the further right, anything in this Section 1 to the contrary notwithstanding,
to accept delivery of an Aircraft under the Aircraft Purchase Agreement on the
Delivery Date thereof by utilization of bridge financing of such Aircraft and
promptly thereafter give the parties hereto a Delivery Notice specifying a
Funding Date not later than 90 days after the Delivery Date of such Aircraft and
no later than the Cut-off Date and otherwise complying with the provisions of
Section 1(b) hereof. All other terms and conditions of this Note Purchase
Agreement shall apply to the financing of any such Aircraft on the re-scheduled
Funding Date therefor except (i) the re-scheduled Funding Date shall be deemed
the Delivery Date of such Aircraft for all purposes of this Section 1, (ii) the
related Financing Agreements (or other financing agreements in the case of a
Special Structure) shall be amended to reflect the original delivery of such
Aircraft to the Company and (iii) the related Financing Agreements shall be
amended to reflect the seller of such Aircraft, and the recipient of payment of
the purchase price therefor, as the Company and (iv) in the case of a Leased
Aircraft, the Aircraft Purchase Agreement Assignment shall be modified to cover
only an assignment of the relevant warranties.

                  (f) If the Scheduled Delivery Date for any Aircraft is delayed
for any reason (including the casualty loss thereof) more than 30 days beyond
the last day of the month set forth opposite such Aircraft under the heading
"Scheduled Delivery Months" in Schedule I hereto, the Company may identify for
delivery a substitute aircraft therefor meeting the following conditions (a
"Substitute Aircraft"): (i) a Substitute Aircraft must be an Airbus A319-100 or
A320-200 aircraft manufactured after the date of this Agreement, (ii) one or
more Substitute Aircraft of the same or different types may be substituted for
one or more Aircraft of the same or different types so long as after giving
effect thereto such substitution does not vary the Mandatory Economic Terms and
(iii) the Company shall be obligated to obtain prior written consent of the
Policy
<PAGE>   9
                                                                               6

Provider and to obtain Rating Agency Confirmation in respect of the replacement
of any Aircraft by Substitute Aircraft. Upon the satisfaction of the conditions
set forth above with respect to a Substitute Aircraft, the Aircraft to be
replaced shall cease to be subject to this Agreement and all rights and
obligations of the parties hereto concerning such Aircraft shall cease, and such
Substitute Aircraft shall become and thereafter be subject to the terms and
conditions of this Agreement to the same extent as such Aircraft.

                  (g) The Company shall have no liability for the failure of the
Pass Through Trustees to purchase Equipment Notes with respect to any Aircraft
or Substitute Aircraft, other than the Company's obligation, if any, to pay the
Deposit Make-Whole Premium pursuant to Section 4(a)(i) of this Agreement.

                  (h) The parties agree that if, in connection with the delivery
of an Aircraft or Substitute Aircraft, any Owner Participant who is to be a
party to any Lease Financing Agreement shall not be a "Citizen of the United
States" within the meaning of Section 40102(a)(15) of the Act, then the
applicable Lease Financing Agreements shall be modified, consistent with the
Mandatory Document Terms, (x) to require such Owner Participant to enter into a
voting trust, voting powers or similar arrangement satisfactory to the Company
that (A) enables such Aircraft or Substitute Aircraft to be registered in the
United States and (B) complies with the FAA regulations issued under the Act
applicable thereto and (y) to be otherwise consistent with such state of
affairs.

                  (i) Anything herein to the contrary notwithstanding, the
Company shall not have the right, and shall not be entitled, at any time to
request the issuance of Equipment Notes of any series to any Pass Through
Trustee in an aggregate principal amount in excess of the amount of the Deposits
then available for withdrawal by the Escrow Agent under and in accordance with
the provisions of the related Deposit Agreement.

                  (j) Notwithstanding the foregoing provisions of this Section
1, and anything herein to the contrary notwithstanding, upon not less than 30
days' prior written notice to the parties hereto, the Company shall have the
right, within 120 days after the date any Aircraft has been financed as an Owned
Aircraft, to sell such Owned Aircraft and transfer title to such Owned Aircraft
to an Owner Trustee for the benefit of an Owner Participant (which shall be a
Qualified Owner Participant) in a transaction in which such Owner Trustee
assumes all of the obligations of the Company under the relevant Equipment Notes
and the Owned Aircraft Indenture on a non-recourse basis (with the Company being
released from such obligations, except to the extent accrued prior thereto),
leases the Aircraft to the Company and assigns such lease to the Loan Trustee
pursuant to an amended and restated trust indenture (a "Sale/Leaseback
Transaction"). In connection with such Sale/Leaseback Transaction, the Company
and the relevant Note Holders will execute and deliver appropriate documentation
permitting the Owner Trustee to assume the obligations of the Company under the
relevant Equipment Notes and the Owned Aircraft Indenture on a non-recourse
basis, releasing the Company from all obligations in respect of such Equipment
Notes and the Owned Aircraft Indenture (except to the extent accrued prior
thereto), and take all other actions as are reasonably necessary to permit such
assumption by the Owner Trustee. In connection with any such Sale/Leaseback
Transaction, the parties hereto agree that (a) the documents to be utilized
shall be (i) an amended and restated participation agreement amending and
restating the Participation Agreement, such amended and
<PAGE>   10
                                                                               7

restated participation agreement to be substantially in the form of the Leased
Aircraft Participation Agreement, among the Company, the relevant Note Holders,
the Owner Participant, the Owner Trustee, and the Loan Trustee , with (x) such
changes to such form to reflect the assumption of such Equipment Notes by the
Owner Trustee on a non-recourse basis rather than the issuance thereof by the
Owner Trustee and original purchase thereof by the Note Holders and also to
reflect the release of the Company from all obligations under such Equipment
Notes and the Owned Aircraft Indenture (except to the extent accrued prior
thereto) and (y) such other changes as may be permitted in accordance with the
provisions of Section 1(c) hereof applicable to a Leased Aircraft Participation
Agreement in connection with a leverage lease transaction, (ii) a lease
agreement, such lease agreement to be substantially in the form of the Lease
between the Company and the Owner Trustee with such changes as may be permitted
in accordance with the provisions of Section 1(c) hereof applicable to the Lease
in connection with a leveraged lease transaction, (iii) an amended and restated
trust indenture amending and restating the relevant Owned Aircraft Indenture,
such amended and restated trust indenture to be substantially in the form of a
Leased Aircraft Indenture, between the Owner Trustee and the Loan Trustee, with
(x) such changes to such form to reflect the assumption of all of the
obligations of the Owner Trustee under relevant Equipment Notes and the relevant
Owned Aircraft Indenture on a non-recourse basis and the release of the
obligations of the Company under such Equipment Notes and the relevant Owned
Aircraft Indenture and (y) such other changes as may be permitted in accordance
with the provisions of Section 1(c) hereof applicable to a Leased Aircraft
Indenture in connection with a leveraged lease transaction, (iv) a purchase
agreement assignment, such purchase agreement assignment to be substantially in
the form of the Aircraft Purchase Agreement Assignment between the Company and
the Owner Trustee with such changes as may be permitted in accordance with the
provisions of Section 1(c) hereof applicable to an Aircraft Purchase Agreement
Assignment in connection with a leveraged lease transaction, and (v) a trust
agreement, such trust agreement to be substantially in the form of a Trust
Agreement, between the Owner Trustee and the Owner Participant with such changes
as may be permitted in accordance with the provisions of Section 1(c) hereof
applicable to a Trust Agreement in connection with a leveraged lease transaction
and (b) the relevant Equipment Notes shall be delivered to the Loan Trustee for
cancellation in exchange for new equipment notes to be issued to the Note
Holders by the Owner Trustee upon the authentication thereof by the Loan
Trustee, such new equipment notes to be substantially in the form contained in
Section 2.01 of the Leased Aircraft Indenture. Such new equipment notes will
have the same payment terms except that in the event that the Company enters
into a Sale/Leaseback Transaction prior to the first Regular Distribution Date
occurring after the issuance of the Equipment Notes relating to that Aircraft,
the Company shall have the right to reoptimize the new equipment notes to be
issued to the Note Holders by the Owner Trustee in compliance with the Mandatory
Economic Terms.

                  Notwithstanding the foregoing, the Company shall not have the
right to enter into a Sale/Leaseback Transaction unless the Company (a) either
(i) causes to be delivered to the Loan Trustee an opinion of counsel to the
effect that the Certificateholders will not recognize income, gain or loss for
Federal income tax purposes as a result of such assumption and release and will
be subject to Federal income tax in the same amounts, in the same manner and at
the same time as would have been the case if such assumption and release had not
occurred and that the Pass Through Trusts will not be subject to Federal income
taxation as a result of such assumption and release or (ii) provides an
indemnification in favor of the holders of the Certificates in form and
substance reasonably satisfactory to the Pass Through Trustees and (b)
<PAGE>   11
                                                                               8

obtains Policy Provider consent and a Rating Agency Confirmation with respect
thereto. In addition, the Company agrees to otherwise comply with the provisions
of Sections 1(c) and 2 hereof in connection with any Sale/Leaseback Transaction.

                  SECTION 2. Conditions Precedent. The obligation of the Pass
Through Trustees to enter into, and to cause the Subordination Agent to enter
into, any Participation Agreement or financing agreement relating to a Special
Structure as directed pursuant to a Delivery Notice and to perform its
obligations thereunder is subject to satisfaction of the following conditions:

                  (a) no Triggering Event shall have occurred;

                  (b) the Company shall have delivered a certificate to each
         such Pass Through Trustee, the Policy Provider and each Liquidity
         Provider stating that (i) such Participation Agreement and the other
         Financing Agreements to be entered into pursuant to such Participation
         Agreement or, in the case of a Special Structure, the financing
         agreements to be entered into in connection with such Special Structure
         do not vary the Mandatory Economic Terms and, except in the case of a
         Special Structure, contain the Mandatory Document Terms, (ii) any
         substantive modification of such Financing Agreements or financing
         agreement relating to a Special Structure from the forms of Financing
         Agreements attached to this Agreement do not materially and adversely
         affect the Policy Provider or the Certificateholders and, in the case
         of a Special Structure, do not expose the Policy Provider, the
         Liquidity Provider or the Certificateholders to any material additional
         risks beyond those to which such persons would have been exposed absent
         such Special Structure, and such certification shall be true and
         correct; and

                  (c) in the case of a Special Structure, a copy of the Rating
         Agency Confirmations and the Policy Provider consent required under
         Section 1(c) shall have been delivered to each such Pass Through
         Trustee.

                  Anything herein to the contrary notwithstanding, the
obligation of each Pass Through Trustee to purchase Equipment Notes shall
terminate on the Cut-off Date.

                  SECTION 3. Representations and Warranties. (a) The Company
represents and warrants that:

                           (i) the Company is duly incorporated, validly
                  existing and in good standing under the laws of the State of
                  Delaware and is a "citizen of the United States" as defined in
                  Section 40102 of the Act, and has the full corporate power,
                  authority and legal right under the laws of the State of
                  Delaware to execute and deliver this Agreement and each
                  Financing Agreement to which it will be a party and to carry
                  out the obligations of the Company under this Agreement and
                  each Financing Agreement to which it will be a party;

                           (ii) the execution and delivery by the Company of
                  this Agreement and the performance by the Company of its
                  obligations under this Agreement have been duly authorized by
                  the Company and will not violate its Certificate of
                  Incorporation or by-laws or (other than any violation that
                  would not result in a Material Adverse Change to the Company)
                  the provisions of any indenture,
<PAGE>   12
                                                                               9

                  mortgage, contract or other agreement to which it is a party
                  or by which it is bound; and

                           (iii) assuming the due authorization, execution and
                  delivery hereof by the other parties hereto this Agreement
                  constitutes the legal, valid and binding obligation of the
                  Company, 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 the rights of creditors generally and by general
                  principles of equity, whether considered in a proceeding at
                  law or in equity.

                  (b) WTC represents and warrants that:

                           (i) WTC is duly incorporated, validly existing and in
                  good standing under the laws of the State of Delaware and is a
                  "citizen of the United States" as defined in Section 40102 of
                  the Act, and has the full corporate power, authority and legal
                  right under the laws of the State of Delaware and the United
                  States pertaining to its banking, trust and fiduciary powers
                  to execute and deliver this Agreement and each Financing
                  Agreement to which it will be a party and to carry out the
                  obligations of WTC, in its capacity as Subordination Agent,
                  Pass Through Trustee or Paying Agent, as the case may be,
                  under this Agreement and each Financing Agreement to which it
                  will be a party;

                           (ii) the execution and delivery by WTC, in its
                  capacity as Subordination Agent, Pass Through Trustee or
                  Paying Agent, as the case may be, of this Agreement and the
                  performance by WTC, in its capacity as Subordination Agent,
                  Pass Through Trustee or Paying Agent, as the case may be, of
                  its obligations under this Agreement have been duly authorized
                  by WTC, in its capacity as Subordination Agent, Pass Through
                  Trustee or Paying Agent, as the case may be, 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 WTC, in its capacity as Subordination
                  Agent, Pass Through Trustee or Paying Agent, as the case may
                  be, 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 the rights of creditors generally and by general
                  principles of equity, whether considered in a proceeding at
                  law or in equity.

                  (c) The Pass Through Trustee hereby confirms to each of the
other parties hereto that its representations and warranties set forth in
Section 7.15 of each Pass Through Trust Agreement are true and correct as of the
date hereof.

                  (d) The Subordination Agent represents and warrants that:
<PAGE>   13
                                                                              10

                           (i) the Subordination Agent is duly incorporated,
                  validly existing and in good standing under the laws of the
                  State of Delaware, and has the full corporate power, authority
                  and legal right under the laws of the State of Delaware and
                  the United States pertaining to its banking, trust and
                  fiduciary powers to execute and deliver this Agreement and
                  each Financing Agreement to which it is or will be a party and
                  to perform its obligations under this Agreement and each
                  Financing Agreement to which it is or will be a party;

                           (ii) this Agreement has been duly authorized,
                  executed and delivered by the Subordination Agent; this
                  Agreement constitutes the legal, valid and binding obligations
                  of the Subordination Agent 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 the rights of creditors
                  generally and by general principles of equity, whether
                  considered in a proceeding at law or in equity;

                           (iii) none of the execution, delivery and performance
                  by the Subordination Agent of this Agreement contravenes any
                  law, rule or regulation of the State of Delaware or any United
                  States governmental authority or agency regulating the
                  Subordination Agent's banking, trust or fiduciary powers or
                  any judgment or order applicable to or binding on the
                  Subordination Agent and do not contravene the Subordination
                  Agent's articles of association or by-laws or result in any
                  breach of, or constitute a default under, any agreement or
                  instrument to which the Subordination Agent is a party or by
                  which it or any of its properties may be bound;

                           (iv) neither the execution and delivery by the
                  Subordination Agent of this Agreement nor the consummation by
                  the Subordination Agent of any of the transactions
                  contemplated hereby requires the consent or approval of, the
                  giving of notice to, the registration with, or the taking of
                  any other action with respect to, any Delaware governmental
                  authority or agency or any federal governmental authority or
                  agency regulating the Subordination Agent's banking, trust or
                  fiduciary powers;

                           (v) there are no Taxes payable by the Subordination
                  Agent imposed by the State of Delaware or any political
                  subdivision or taxing authority thereof in connection with the
                  execution, delivery and performance by the Subordination Agent
                  of this Agreement (other than franchise or other taxes based
                  on or measured by any fees or compensation received by the
                  Subordination Agent for services rendered in connection with
                  the transactions contemplated by the Intercreditor Agreement
                  or any of the Liquidity Facilities), and there are no Taxes
                  payable by the Subordination Agent imposed by the State of
                  Delaware or any political subdivision thereof in connection
                  with the acquisition, possession or ownership by the
                  Subordination Agent of any of the Equipment Notes (other than
                  franchise or other taxes based on or measured by any fees or
                  compensation received by the Subordination Agent for services
                  rendered in connection with the
<PAGE>   14
                                                                              11

                  transactions contemplated by the Intercreditor Agreement or
                  any of the Liquidity Facilities); and

                           (vi) there are no pending or threatened actions or
                  proceedings against the Subordination Agent before any court
                  or administrative agency which individually or in the
                  aggregate, if determined adversely to it, would materially
                  adversely affect the ability of the Subordination Agent to
                  perform its obligations under this Agreement.

                  (e) The Escrow Agent represents and warrants that:

                           (i) the Escrow Agent is duly incorporated, validly
                  existing and in good standing under the laws of the State of
                  Delaware and has the full corporate power, authority and legal
                  right under the laws of the State of Delaware pertaining to
                  its banking, trust and fiduciary powers to execute and deliver
                  this Agreement, each Deposit Agreement and each Escrow and
                  Paying Agent Agreement (collectively, the "Escrow Agent
                  Agreements") and to carry out the obligations of the Escrow
                  Agent under each of the Escrow Agent Agreements;

                           (ii) the execution and delivery by the Escrow Agent
                  of each of the Escrow Agent Agreements and the performance by
                  the Escrow Agent of its obligations hereunder and thereunder
                  have been duly authorized by the Escrow Agent 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) each of the Escrow Agent Agreements constitutes
                  the legal, valid and binding obligations of the Escrow Agent
                  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 the
                  rights of creditors generally and by general principles of
                  equity, whether considered in a proceeding at law or in
                  equity.

                  (f) The Paying Agent represents and warrants that:

                           (i) the Paying Agent is duly incorporated, validly
                  existing and in good standing under the laws of the State of
                  Delaware and has the full corporate power, authority and legal
                  right under the laws of the State of Delaware and the United
                  States pertaining to its banking, trust and fiduciary powers
                  to execute and deliver this Agreement and the Escrow and
                  Paying Agent Agreement (collectively, the "Paying Agent
                  Agreements") and to carry out the obligations of the Paying
                  Agent under each of the Paying Agent Agreements;

                           (ii) the execution and delivery by the Paying Agent
                  of each of the Paying Agent Agreements and the performance by
                  the Paying Agent of its obligations hereunder and thereunder
                  have been duly authorized by the Paying Agent and will not
                  violate its articles of association or by-laws or the
                  provisions
<PAGE>   15
                                                                              12

                  of any indenture, mortgage, contract or other agreement to
                  which it is a party or by which it is bound; and

                           (iii) each of the Paying Agent Agreements constitutes
                  the legal, valid and binding obligations of the Paying Agent
                  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 the
                  rights of creditors generally and by general principles of
                  equity, whether considered in a proceeding at law or in
                  equity.

                  SECTION 4. Covenants. (a) The Company covenants with each of
the other parties hereto that:

                  (i) on the date that the Depositary is obligated to pay the
         amount of the Final Withdrawal to the Paying Agent pursuant to a
         Deposit Agreement relating to any Trust, the Company shall pay to the
         Pass Through Trustee of such Trust no later than 12:30 p.m. (New York
         time) an amount equal to the Deposit Make-Whole Premium, if any,
         required to be paid in respect of such Final Withdrawal amount;

                  (ii) subject to Section 4(a)(iv) of this Agreement, the
         Company shall at all times maintain its corporate existence;

                  (iii) the Company shall at all times remain a U.S. Air Carrier
         (as defined in the Financing Agreements) and shall at all times be
         otherwise certificated and registered to the extent necessary to
         entitle (i) in the case of Leased Aircraft, the Owner Trustee (and the
         Loan Trustee as assignee of the Owner Trustee's rights under each
         Lease) to the rights afforded to lessors of aircraft equipment under
         Section 1110 and (ii) in the case of Owned Aircraft, the Loan Trustee
         to the rights afforded to secured parties of aircraft equipment under
         Section 1110;

                  (iv) Section 13.2.1 of each Lease is hereby incorporated by
         reference herein;

                  (v) the Company agrees to provide written notice to each of
         the parties hereto of the occurrence of the Cut-off Date no later than
         one Business Day after the date thereof; such notice to refer
         specifically to the Pass Through Trustee's obligation to assign,
         transfer and deliver all of its right, title and interest to the Trust
         Property (as defined in each Pass Through Trust Agreement) to the
         trustee of the Related Trust (as defined in each Pass Through Trust
         Agreement) in accordance with Section 11.01 of each of the Pass Through
         Trust Agreements;

                  (vi) the Company shall not issue Series D Equipment Notes
         pursuant to any Owned Aircraft Indenture or Leased Aircraft Indenture
         unless it shall have obtained written confirmation from each Rating
         Agency that the issuance of such Series D Equipment Notes will not
         result in (i) a reduction of the rating for any Class of Certificates
         below the then current rating for such Class of Certificates without
         regard to the Policy or (ii) a withdrawal or suspension of the rating
         of any Class of Certificates; if such conditions to the issuance of
         Series D Equipment Notes are satisfied, the parties hereto agree to
         enter into such amendments and modifications to the Intercreditor
<PAGE>   16
                                                                              13

         Agreement, each Pass Through Trust Agreement and the other Financing
         Agreements as shall be reasonably requested by the Company to
         facilitate the issuance of the same and any Series D Pass Through
         Certificates. The Company will (i) cause the Indenture under which any
         Series D Equipment Notes are issued to provide for the subordination of
         the Series D Equipment Notes to the Series C Equipment Notes, the
         Policy Obligations (as defined in the Intercreditor Agreement), the
         Series G Equipment Notes and the Liquidity Obligations (as defined in
         the Intercreditor Agreement) in the same manner as the Series C
         Equipment Notes are subordinated to the Policy Obligations, the Series
         G Equipment Notes and the Liquidity Obligations and (ii) if Series D
         Equipment Notes are initially issued to other than the pass through
         trustee for the Class D Certificates (as defined in the Intercreditor
         Agreement), (A) cause such Series D Equipment Notes to be subject to
         the provisions of the Intercreditor Agreement that allow for the
         "Controlling Party" (as defined in the Intercreditor Agreement), during
         the continuance of an "Indenture Default" (as defined in the
         Intercreditor Agreement), to direct the Loan Trustee in taking action
         under the applicable Indenture and (B) cause the Indenture under which
         such Series D Equipment Notes are issued to include, in substance, the
         provisions set forth in Exhibit D to this Agreement; and

                  (vii) If the Depositary's long-term unsecured debt rating
         shall at any time fall below BBB+ from Standard & Poor's or Baa1 from
         Moody's, the Company shall, within 45 days of such event occurring,
         cause the Depositary to be replaced with a depository bank that has
         short-term ratings of at least P-1 from Moody's and A-1 from Standard &
         Poor's and long-term unsecured ratings of at least A2 from Moody's and
         A from Standard & Poor's (a "Replacement Depositary") on the following
         terms and preconditions:

                  (A) the Company shall obtain written confirmation from each
         Rating Agency that such replacement will not cause a reduction of any
         rating then in effect for any Class of Certificates by such Rating
         Agency (without regard to any downgrading of any rating of the
         Depositary being replaced and without regard to the Policy);

                  (B) the Company shall pay all fees, expenses and other amounts
         then owing to the replaced Depositary; and

                  (C) the Company shall cause the Escrow Agent and the
         Replacement Depositary to enter into a Replacement Deposit Agreement
         for each Class of Certificates and shall cause the Replacement
         Depositary to deliver to the Company, the Policy Provider and each
         Rating Agency legal opinions and other closing documentation
         substantially similar in scope and substance as those that were
         delivered by the Depositary being replaced in connection with the
         execution and delivery of the Deposit Agreement being replaced.

                  Upon satisfaction of the foregoing conditions, the Company
         shall instruct each Pass Through Trustee, and each Pass Through Trustee
         agrees, to execute and deliver to the Escrow Agent a duly completed
         Withdrawal Certificate (as defined in the Escrow and Paying Agent
         Agreements) together with a Notice of Replacement Withdrawal (as
         defined in the Escrow and Paying Agent Agreements).
<PAGE>   17
                                                                              14

                  Each of the parties hereto agrees, at the Company's request,
         to enter into any amendments to this Agreement, the Escrow and Paying
         Agent Agreements and any other Operative Agreements as may be necessary
         or desirable to give effect to the replacement of the Depositary with
         the Replacement Depositary and the replacement of the Deposit
         Agreements with the Replacement Deposit Agreements.

                  Upon the execution and delivery of the Replacement Deposit
         Agreements, the Replacement Depositary shall be deemed to be the
         Depositary with all of the rights and obligations of the Depositary
         hereunder and under the other Operative Agreements and the Replacement
         Deposit Agreements shall be deemed to be the Deposit Agreements
         hereunder and under the other Operative Agreements, except that the
         obligations of the replaced Depositary under the last two sentences of
         Section 1.4(a) of its Deposit Agreements shall remain in full force and
         effect notwithstanding the execution and delivery of the Replacement
         Deposit Agreements.

                  (b) WTC, in its individual capacity, covenants with each of
the other parties to this Agreement that it will, immediately upon obtaining
knowledge of any facts that would cast doubt upon its continuing status as a
"citizen of the United States" as defined in Section 40102 of the Act and
promptly upon public disclosure of negotiations in respect of any transaction
which would or might adversely affect such status, notify in writing all parties
hereto of all relevant matters in connection therewith. Upon WTC giving any such
notice, WTC shall, subject to Section 8.02 of any Indenture then entered into,
resign as Loan Trustee in respect of such Indenture.

                  (c) the Subordination Agent covenants with each of the other
parties hereto that it will not agree or consent to any amendment or
modification to any Liquidity Facility, the Policy Provider Agreement or the
Intercreditor Agreement without the Company's consent, if such amendment or
modification would adversely affect the interests of the Company.

                  (d) The Escrow Agent covenants with each of the other parties
hereto that it will not agree or consent to any amendment or modification to any
Deposit Agreement or Escrow and Paying Agent Agreement without the Company's
consent, if such amendment or modification would adversely affect the interests
of the Company.

                  SECTION 5. Notices. Unless otherwise expressly permitted by
the terms hereof, all notices, requests, demands, authorizations, directions,
consents, waivers and other communications required or permitted to be made,
given, furnished or filed hereunder shall be in writing (it being understood
that the specification of a writing in certain instances and not in others does
not imply an intention that a writing is not required as to the latter), shall
refer specifically to this Agreement, and shall be personally delivered, sent by
facsimile or telecommunication transmission (which in either case provides
written confirmation to the sender of its delivery), sent by registered mail or
certified mail, return receipt requested, postage prepaid, or sent by overnight
courier service, in each case to the respective address or facsimile number set
forth for such party below the signature of such party at the foot of this
Agreement, or to such other address, facsimile or other number as each party
hereto may hereafter specify by notice to the other parties hereto. Notice shall
be given to the Policy Provider at the address specified in the Policy Provider
Agreement. Each such notice, request, demand, authorization, direction,
<PAGE>   18
                                                                              15

consent, waiver or other communication 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.

                  SECTION 6. Expenses. (a) The Company agrees to pay to the
Subordination Agent when due for application in accordance with the
Intercreditor Agreement an amount or amounts equal to the fees payable to the
Liquidity Provider under Section 2.03 of each Liquidity Facility and the related
Fee Letter (as defined in the Intercreditor Agreement) multiplied by a fraction
the numerator of which shall be the then outstanding aggregate amount of the
Deposits under the Deposit Agreements and the denominator of which shall be the
sum of (x) the then outstanding aggregate principal amount of the Series G
Equipment Notes and Series C Equipment Notes issued under all of the Indentures
and (y) the then outstanding aggregate amount of the Deposits under the Deposit
Agreements.
                  (b) The Company agrees to pay to the Subordination Agent when
due for application in accordance with the Intercreditor Agreement an amount or
amounts equal to the fees payable to the Policy Provider under Section 3.02 of
the Policy Provider Agreement multiplied by a fraction the numerator of which
shall be the then outstanding aggregate amount of the Deposits under the Deposit
Agreement pertaining to the Class G Trust and the denominator of which shall be
the sum of (x) the then outstanding aggregate principal amount of the Series A
Equipment Notes issued under all of the Indentures and (y) the then outstanding
aggregate amount of the Deposits under the Deposit Agreement pertaining to the
Class G Trust.

                  (c) So long as no Equipment Notes have been issued in respect
of any Aircraft, the Company agrees to pay (i) to the Subordination Agent when
due (A) the amount equal to interest on any Downgrade Advance (other than any
Applied Downgrade Advance) payable under Section 3.07 of each Liquidity Facility
minus Investment Earnings while such Downgrade Advance shall be outstanding, (B)
the amount equal to interest on any Non-Extension Advance (other than any
Applied Non-Extension Advance) payable under Section 3.07 of each Liquidity
Facility minus Investment Earnings while such Non-Extension Advance shall be
outstanding and (C) any other amounts owed to the Liquidity Provider by the
Subordination Agent as borrower under each Liquidity Facility (other than
amounts due as repayment of advances thereunder or as interest on such advances,
except to the extent payable pursuant to clause (A) or (B)), (ii) all
compensation and reimbursement of expenses, disbursements and advances payable
by the Company under the Pass Through Trust Agreements, (iii) all compensation
and reimbursement of expenses and disbursements payable to the Subordination
Agent under the Intercreditor Agreement (as may be modified by any separate
letter agreement) except with respect to any Unindemnified Taxes incurred by the
Subordination Agent in connection with the transactions contemplated by the
Intercreditor Agreement, (iv) all compensation and reimbursement of expenses and
disbursements payable to the Policy Provider under the Policy Provider
Agreement, and (v) in the event the Company requests any amendment to any
Operative Agreement, all reasonable fees and expenses (including, without
limitation, fees and disbursements of counsel) of the Escrow Agent, the Paying
Agent and/or the Policy Provider in connection therewith. For purposes of this
Section 6(b), the terms "Applied Downgrade Advance", "Applied Non-Extension
Advance", "Downgrade Advance", "Investment Earnings" and "Non-Extension Advance"
shall have the meanings specified in each Liquidity Facility.
<PAGE>   19
                                                                              16

                  SECTION 7. Further Assurances. Each party hereto shall duly
execute, acknowledge and deliver, or shall cause to be executed, acknowledged
and delivered, all such further agreements, instruments, certificates or
documents, and shall do and cause to be done such further acts and things, in
any case, as any other party hereto shall reasonably request in connection with
its administration of, or to carry out more effectually the purposes of, or to
better assure and confirm unto it the rights and benefits to be provided under,
this Agreement.

                  SECTION 8. Miscellaneous. (a) Provided that the transactions
contemplated hereby have been consummated, and except as otherwise provided for
herein, the representations, warranties and agreements herein of the Company,
the Subordination Agent, the Escrow Agent and the Pass Through Trustee, and the
Company's, the Subordination Agent's, the Escrow Agent's and the Pass Through
Trustee's obligations under any and all thereof, shall survive the financing of
each Aircraft hereunder but shall terminate on the expiration or other
termination of this Agreement.

                  (b) This Agreement may be executed in any number of
counterparts (and each of the parties hereto shall not be required to execute
the same counterpart). Each counterpart of this Agreement, including a signature
page executed by each of the parties hereto, shall be an original counterpart of
this Agreement, but all of such counterparts together shall constitute one
instrument. Neither this Agreement nor any of the terms hereof may be
terminated, amended, supplemented, waived or modified orally, but only by an
instrument in writing signed by the party against which the enforcement of the
termination, amendment, supplement, waiver or modification is sought. The index
preceding this Agreement and the headings of the various Sections of this
Agreement are for convenience of reference only and shall not modify, define,
expand or limit any of the terms or provisions hereof. The terms of this
Agreement shall be binding upon, and shall inure to the benefit of, the Company
and its successors and permitted assigns, the Pass Through Trustee and its
successors as Pass Through Trustee (and any additional trustee appointed) under
any of the Pass Through Trust Agreements, the Escrow Agent and its successors as
Escrow Agent under the Escrow and Paying Agent Agreements, the Paying Agent and
its successors as Paying Agent under the Escrow and Paying Agent Agreement and
the Subordination Agent and its successors as Subordination Agent under the
Intercreditor Agreement.

                  (c) This Agreement is not intended to, and shall not, provide
any person not a party hereto (other than the Initial Purchasers and each of the
beneficiaries of Section 6 hereof) with any rights of any nature whatsoever
against any of the parties hereto, and no person not a party hereto (other than
the Initial Purchasers and each of the beneficiaries of Section 6 hereof) shall
have any right, power or privilege in respect of, or have any benefit or
interest arising out of, this Agreement. To the extent that this Agreement
expressly confers upon, gives or grants any right, power, privilege, benefit,
interest, remedy or claim to any of the beneficiaries of Section 6 hereof
(including, but not limited to rights, powers, privileges, benefits, interests,
remedies and claims under Section 6) each such party is hereby recognized as a
third party beneficiary hereunder and may enforce any such right, power,
privilege, benefit, interest, remedy or claim.
<PAGE>   20
                                                                              17

                  SECTION 9. Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY,
AND CONSTRUED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK. THIS
AGREEMENT IS BEING DELIVERED IN THE STATE OF NEW YORK.
<PAGE>   21
                                                                              18

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

                                       AMERICA WEST AIRLINES, INC.


                                       By
                                         --------------------------------------
                                         Name:
                                         Title:

                                       Address: 4000 East Sky Harbor Boulevard
                                                Phoenix, Arizona 85034
                                                Attention: Vice President
                                                - Treasurer
                                                Facsimile:  (602) 693-5886


                                       WILMINGTON TRUST COMPANY,
                                       not in its individual capacity, except as
                                       otherwise provided herein, but solely as
                                       Pass Through Trustee


                                       By
                                         --------------------------------------
                                         Name:
                                         Title:

                                       Address: Rodney Square North

                                                1100 North Market Street
                                                Wilmington, Delaware 19890
                                                Attention:  Corporate Trust
                                                             Administration
                                                Facsimile:  (302) 651-8882
<PAGE>   22
                                                                              19

                                       WILMINGTON TRUST COMPANY,
                                       not in its individual capacity, except as
                                       otherwise provided herein, but solely as
                                       Subordination Agent


                                       By
                                         --------------------------------------
                                         Name:
                                         Title:

                                       Address: Rodney Square North
                                                1100 North Market Street
                                                Wilmington, Delaware 19890
                                                Attention:  Corporate Trust
                                                             Administration
                                                Facsimile:  (302) 651-8882


                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent


                                       By
                                         --------------------------------------
                                          Name:
                                          Title:

                                       Address: Rodney Square North
                                                1100 North Market Street
                                                Wilmington, Delaware 19890
                                                Attention:  Corporate Trust
                                                             Administration
                                                Facsimile:  (302) 651-8882


                                       WILMINGTON TRUST COMPANY,
                                       as Paying Agent

                                       By
                                         --------------------------------------
                                          Name:
                                          Title:

                                       Address: Rodney Square North
                                                1100 North Market Street
                                                Wilmington, Delaware 19890
                                                Attention:  Corporate Trust
                                                             Administration
                                                Facsimile:  (302) 651-8882

<PAGE>   23
                                  SCHEDULE I to
                             Note Purchase Agreement

                     AIRCRAFT AND SCHEDULED DELIVERY MONTHS

<TABLE>
<CAPTION>
                                         Expected                     Expected
                                       Registration                Manufacturer's            Scheduled
        Aircraft Type                     Number                    Serial Number          Delivery Month
        -------------                     ------                    -------------          --------------
<S>                                    <C>                         <C>                    <C>
           A319-132                       N807AW                        1064              August 1999
           A319-132                       N808AW                        1088              September 1999
           A319-132                       N809AW                        1111              October 1999
           A319-132                       N810AW                        1116              November 1999
           A319-132                       N811AW                        1178              February 2000
           A320-232                       N654AW                        1050              August 1999
           A320-232                       N655AW                        1075              September 1999
           A320-232                       N656AW                        1079              October 1999
           A320-232                       N657AW                        1083              October 1999
           A320-232                       N658AW                        1166              February 2000
</TABLE>
<PAGE>   24
                                 SCHEDULE II to
                             Note Purchase Agreement

                          PASS THROUGH TRUST AGREEMENTS

Pass Through Trust Agreement dated as of the Issuance Date between the Company
and the Pass Through Trustee in respect of America West Airlines Pass Through
Trust, Series 1999-1G-O.

Pass Through Trust Agreement dated as of the Issuance Date between the Company
and the Pass Through Trustee in respect of America West Airlines Pass Through
Trust, Series 1999-1C-O.
<PAGE>   25
                                 SCHEDULE III to
                             Note Purchase Agreement

                               DEPOSIT AGREEMENTS

Deposit Agreement (Class G) dated as of the Issuance Date between the Depositary
and the Escrow Agent.

Deposit Agreement (Class C) dated as of the Issuance Date between the Depositary
and the Escrow Agent.
<PAGE>   26
                                 SCHEDULE IV to
                             Note Purchase Agreement

                       ESCROW AND PAYING AGENT AGREEMENTS

Escrow and Paying Agent Agreement (Class G) dated as of the Issuance Date among
the Escrow Agent, the Initial Purchasers, the Pass Through Trustee and the
Paying Agent.

Escrow and Paying Agent Agreement (Class C) dated as of the Issuance Date among
the Escrow Agent, the Initial Purchasers, the Pass Through Trustee and the
Paying Agent.
<PAGE>   27
                                  SCHEDULE V to
                             Note Purchase Agreement

                            MANDATORY DOCUMENT TERMS

                       (cross references to be confirmed)

The terms "Trust Indenture Form", "Lease Form" and "Participation Agreement
Form" shall have the respective meanings specified in Schedule VI to the Note
Purchase Agreement.

1.       May not modify in any material adverse respect the Granting Clause of
         the Trust Indenture Form so as to deprive the Note Holders of a
         security interest in and mortgage lien on the Aircraft and, in the case
         of a Leased Aircraft Indenture, the Lease or to eliminate any of the
         "Secured Obligations" as defined therein or otherwise modify in any
         material adverse respect as regards the interests of the Note Holders,
         the Subordination Agent, the Liquidity Provider, the Policy Provider or
         the Mortgagee the provisions of Article II or III or in the case of a
         Leased Aircraft Indenture Section 4.02, 4.03, 4.04, 5.02, 5.06,
         9.01(b), 10.04, 10.11 or 10.12 of the Trust Indenture Form or in the
         case of an Owned Aircraft Indenture Article IV, Section 5.01, 5.02,
         6.02, 10.01, 11.04, 11.11 or 11.12 of the Trust Indenture Form.

2.       May not modify in any material adverse respect as regards the interests
         of the Note Holders, the Subordination Agent, the Liquidity Provider,
         the Policy Provider or the Mortgagee the provisions of Section
         3.2.1(e), 3.3(c), 4.7, the final sentence of 7.1.1, 10.3.1(d)(ii),
         13.3, 16, 17.3, 18.3 or 18.6(a) of the Lease Form or otherwise modify
         the terms of the Lease Form so as to deprive the Mortgagee of rights
         expressly granted to the "Mortgagee" therein.

3.       May not modify in any material adverse respect as regards the interests
         of the Note Holders, the Subordination Agent, the Liquidity Provider or
         the Mortgagee the provisions of Section (Owned Aircraft Section
         references shown in '[ ]') 5.1.9[3.1.7], 5.1.10[3.1.8], 5.1.11[3.1.9],
         5.1.12[3.1.10], 7.5[5.3], 12[9], 15.7(a)[11.7(a)] or 15.9[11.9] of the
         Participation Agreement Form or of the provisions of Section
         5.1.2(xxiii)[3.1.2(xvi)] or 10.1.1(a)(iv) of the Participation
         Agreement Form so as to eliminate the requirement to deliver to the
         Loan Participant or the Mortgagee, as the case may be, the legal
         opinions to be provided to such Persons thereunder (recognizing that
         the lawyers rendering such opinions may be changed) or of the
         provisions of Section 7.6.11(a)(ii)[5.4.5(a)(ii)] of the Participation
         Agreement Form as regards the rights of the Mortgagee thereunder or of
         the provisions of Section 5.1.16[3.1.14] of the Participation Agreement
         Form so as to deprive the Note Holders of a first priority security
         interest as provided therein in and mortgage lien on the Aircraft and
         the Lease or otherwise modify the terms of the Participation Agreement
         Form to deprive the Trustees, the Subordination Agent, the Liquidity
         Providers or the Mortgagee of any indemnity or right of reimbursement
         in its favor for Expenses or Taxes.
<PAGE>   28
                                                                               2

4.       May not modify, in any material adverse respect as regards the
         interests of the Note Holders, the Subordination Agent, the Liquidity
         Providers or the Mortgagee, the definition of "Make Whole Amount" in
         Annex A to the Participation Agreement Form.

Notwithstanding the foregoing, any such Mandatory Document Term may be modified
to correct or supplement any such provision which may be defective or to cure
any ambiguity or correct any mistake, provided that any such action shall not
materially adversely affect the interests of the Note Holders, the Subordination
Agent, the Liquidity Providers, the Policy Provider, the Mortgagee or the
Certificateholders.
<PAGE>   29
                                 SCHEDULE VI to
                             Note Purchase Agreement

                            MANDATORY ECONOMIC TERMS

<TABLE>
<CAPTION>
Equipment Notes
---------------
<S>                                       <C>
Obligor:                                  America West Airlines, Inc. or an Owner Trust

Maximum Principal Amount:                 the maximum principal amount of all
                                          the Equipment Notes issued with
                                          respect to an Aircraft may not exceed
                                          the maximum principal amount of
                                          Equipment Notes indicated for each
                                          such Aircraft as set forth in
                                          "Offering Memorandum Summary --
                                          Equipment Notes and the Aircraft"
                                          under the column "Maximum Principal
                                          Amount of Equipment Notes";

Initial Average Life:                     the average life per aircraft of the
                                          Series G Equipment Notes shall not be
                                          less than 10.5 years or extend beyond
                                          13.0 years and of the Series C
                                          Equipment Notes shall not be less than
                                          2.0 years or extend beyond 3.5 years,
                                          in each case from the Issuance Date;

Average Life (in years):                  as of the first Regular Distribution
                                          Date following the delivery of the
                                          last Aircraft to be delivered, the
                                          average life of the Class G
                                          Certificates and the Class C
                                          Certificates shall not extend beyond,
                                          respectively, 11.5 years and 3.0 years
                                          from the Issuance Date;

Loan to Aircraft Value:                   the loan to aircraft value ratio with
                                          respect to each Aircraft at the time
                                          of issuance of the related Equipment
                                          Notes and on any Regular Distribution
                                          Date thereafter shall not exceed the
                                          percentages set forth in the following
                                          table:
</TABLE>

<TABLE>
<CAPTION>

                                                             SERIES G                    SERIES C
                              AIRCRAFT TYPE              EQUIPMENT NOTES              EQUIPMENT NOTES
                              -------------              ---------------              ---------------
<S>                           <C>                        <C>                          <C>
                              A319-100                         57%                          62%
                              A320-200                         57%                          62%
</TABLE>

<TABLE>
<CAPTION>
<S>                           <C>

                              (in each case computed on the basis of an assumed
                              value of such Aircraft no greater than the value
                              for such Aircraft set forth under "Offering
                              Memorandum Summary -- Equipment Notes and the
                              Aircraft" under the column "Appraised Value" and
                              the Depreciation Assumption defined under
                              "Offering Memorandum Summary -- Loan to Aircraft
                              Value Ratios")

</TABLE>
<PAGE>   30
                                                                               2

<TABLE>
<CAPTION>
<S>                                       <C>
Final Maturity Date:                      the final maturity date of (a) the
                                          Series G Equipment Notes may not be
                                          extended beyond January 2, 2019 and
                                          (b) the Series C Equipment Notes may
                                          not be extended beyond January 2,
                                          2006;

Principal Amount:                         the original aggregate principal
                                          amount of all of the Equipment Notes
                                          of each Series shall not exceed the
                                          original aggregate face amount of the
                                          Certificates issued by the
                                          corresponding Trust and the original
                                          aggregate principal amount of all
                                          Equipment Notes for all Aircraft shall
                                          not exceed the aggregate face value
                                          amount of all Certificates;

Debt Rate:                                the interest rate applicable to each
                                          Series of Equipment Notes must be
                                          equal to the rate applicable to the
                                          Certificates issued by the
                                          corresponding Pass Through Trust;

Payment Due Rate:                         Debt Rate plus 1% per annum

Payment Dates:                            January 2 and July 2 commencing with
                                          the first such date after the
                                          applicable Equipment Notes are issued

Make-Whole Premiums:                      as provided in Article II of the form
                                          of Trust Indenture marked as Exhibits
                                          A-3 and C-2 of the Note Purchase
                                          Agreement (the "Trust Indenture Form")

Redemption and Purchase:                  as provided in Article II of the Trust
                                          Indenture Form

Lease
-----

Term:                                     The Base Lease Term shall expire by
                                          its terms on or after final maturity
                                          date of the related Series G or Series
                                          C Equipment Notes

Lease Payment Dates:                      January 2 and July 2 commencing with
                                          the first such date after the Lease is
                                          entered into, to and including the
                                          last such date in the Term

Minimum Rent:                             Basic Rent due and payable on each
                                          Payment Date shall be at least
                                          sufficient to pay in full, as of such
                                          Payment Date (assuming timely payment
                                          of the related Equipment Notes prior
                                          to such Date), the aggregate principal
                                          amount of scheduled installments due
                                          on the related Equipment Notes
                                          outstanding on such Payment Date
                                          together with accrued and unpaid
                                          interest thereon
</TABLE>
<PAGE>   31
                                                                               3

<TABLE>
<CAPTION>
<S>                                       <C>
Supplemental Rent:                        Sufficient to cover the sums described
                                          in clauses (a) through (d) of such
                                          term as defined in Annex A to the form
                                          of Lease (the "Lease Form") marked as
                                          Exhibit A-2 of the Note Purchase
                                          Agreement

EBO Amount (if any):                      At all times equal to or greater than
                                          the then outstanding principal amount
                                          of the related Equipment Notes
                                          together with accrued interest thereon

Stipulated Loss Value:                    At all times equal to or greater than
                                          the then outstanding principal amount
                                          of the related Equipment Notes
                                          together with accrued interest thereon

Termination Value:                        At all times equal to or greater than
                                          the then outstanding principal amount
                                          of the related Equipment Notes
                                          together with accrued interest thereon

All-risk hull insurance:                  not less than Stipulated Loss Value,
                                          subject to Lessee's right to
                                          self-insure on terms no more favorable
                                          to Lessee in any material respect than
                                          those set forth in Annex D of the form
                                          of Lease marked as Exhibit A-2.

Minimum Liability Insurance Amount:       as set forth in Schedule 1 to the form
                                          of Lease marked as Exhibit A-2.

Payment Due Rate:                         as set forth in Annex A to the form of
                                          Lease marked as Exhibit A-2.

SLV Rate:                                 as set forth in Schedule 1 to the form
                                          of Lease marked as Exhibit A-2.
</TABLE>


Participation Agreement

Mortgagee, Subordination Agent, Liquidity Providers, the Policy Provider, Pass
Through Trustees, and Escrow Agents indemnified against Expenses and Taxes to
the extent set forth in Section 9 of the form of the Participation Agreement
(the "Participation Agreement Form") marked as Exhibits A-1 and C-1 to the Note
Purchase Agreement
<PAGE>   32
                                 SCHEDULE VII to
                             Note Purchase Agreement

                         AGGREGATE AMORTIZATION SCHEDULE

<TABLE>
<CAPTION>
                                     1999-1G Trust Scheduled                 1999-1C Trust Scheduled
  Date                                   Principal Payment                       Principal Payment
  ----                                   -----------------                       -----------------
<S>                                  <C>                                 <C>
January 2, 2000                        $      5,387,382.98                          $3,085,129.91
July 2, 2000                                          0.00                                   0.00
January 2, 2001                               6,414,664.01                           2,507,586.93
July 2, 2001                                          0.00                                   0.00
January 2, 2002                               7,060,279.46                           3,770,663.17
July 2, 2002                                          0.00                                   0.00
January 2, 2003                               8,014,608.99                           3,987,376.87
July 2, 2003                                          0.00                                   0.00
January 2, 2004                               9,365,617.80                           3,958,605.13
July 2, 2004                                          0.00                                   0.00
January 2, 2005                              12,495,401.20                           1,685,711.66
July 2, 2005                                          0.00                                   0.00
January 2, 2006                              13,083,696.06                           1,162,926.33
July 2, 2006                                          0.00                                   0.00
January 2, 2007                              11,209,723.45                                   0.00
July 2, 2007                                  3,095,483.98                                   0.00
January 2, 2008                               3,106,003.55                                   0.00
July 2, 2008                                  6,408,747.64                                   0.00
January 2, 2009                               3,385,324.07                                   0.00
July 2, 2009                                  5,670,310.34                                   0.00
January 2, 2010                               3,069,836.70                                   0.00
July 2, 2010                                  4,243,182.39                                   0.00
January 2, 2011                               2,501,500.00                                   0.00
July 2, 2011                                  6,422,511.70                                   0.00
January 2, 2012                               2,266,831.17                                   0.00
July 2, 2012                                  8,733,335.37                                   0.00
January 2, 2013                               4,991,073.36                                   0.00
July 2, 2013                                  7,171,109.55                                   0.00
January 2, 2014                               8,144,628.68                                   0.00
July 2, 2014                                 12,065,086.82                                   0.00
January 2, 2015                               6,717,588.43                                   0.00
July 2, 2015                                  4,826,264.36                                   0.00
January 2, 2016                              12,146,939.44                                   0.00
July 2, 2016                                  2,561,617.20                                   0.00
January 2, 2017                              14,110,504.32                                   0.00
July 2, 2017                                  4,443,412.96                                   0.00
January 2, 2018                              21,448,979.41                                   0.00
July 2, 2018                                    633,454.03                                   0.00
January 2, 2019                              12,472,900.58                                   0.00
</TABLE>
<PAGE>   33
                                   ANNEX A to
                             Note Purchase Agreement

                                   DEFINITIONS

"Act" means 49 U.S.C. Sections 40101-46507.

"Adjusted Treasury Yield" means the Treasury Yield plus, in the case of a
distribution to holders of Class G Certificates, 225 basis points and, in the
case of a distribution to holders of Class C Certificates, 250 basis points.

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

"Aircraft" has the meaning set forth in the second recital to the Note Purchase
Agreement.

"Aircraft Purchase Agreement" means the Airbus A319/A320 Purchase Agreement,
dated as of September 12, 1997, between the Company and the Manufacturer
(including all exhibits thereto, together with all letter agreements entered
into that by their terms constitute part of any such Purchase Agreement).

"Aircraft Purchase Agreement Assignment" means an Assignment and Delegation
Agreement substantially in the form of Exhibit A-4 to the Note Purchase
Agreement.

"Assumed Amortization Schedule" means Schedule VII to the Note Purchase
Agreement.

"Average Life Date" means, for any Equipment Note, the date which follows the
time of determination by a period equal to the Remaining Weighted Average Life
of such Equipment Note.

"Bankruptcy Code" means the United States Bankruptcy Code, 11 U.S.C. Sections
101 et seq.

"Business Day" means any day, other than a Saturday, Sunday or other day on
which commercial banks are authorized or required by law to close in New York,
New York, Phoenix, Arizona, Hartford, Connecticut or Wilmington, Delaware.

"Certificate" has the meaning set forth in the third recital to the Note
Purchase Agreement.

"Certificateholder" means the Person in whose name a Certificate is registered
in the Register.

"Class" means the class of Certificates issued by each Pass Through Trust.

"Class G Trust " has the meaning specified in the Intercreditor Agreement.

"Company" means America West Airlines, Inc., a Delaware corporation.
<PAGE>   34
                                                                               2

"Corporate Trust Office" with respect to any Pass Through 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 day after the Delivery Period
Termination Date and (b) the date on which a Triggering Event occurs.

"Delivery Period Termination Date" means the earlier of (a) May 30, 2000, or, if
the Equipment Notes relating to all of the Aircraft (or Substitute Aircraft in
lieu thereof) have not been purchased by the Pass Through 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, August 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 Pass Through
Trustees in accordance with the Note Purchase Agreement.

"Delivery Date" means the Business Day on which an Aircraft is delivered to and
accepted by the Company or otherwise becomes subject to any Financing Agreement.

"Deposit" has the meaning set forth in the fifth recital to the Note Purchase
Agreement.

"Deposit Agreement" shall mean the Initial Deposit Agreements set forth on
Schedule III hereto and, from and after the transfer of the Deposits to a
Replacement Depositary, shall refer to the corresponding Replacement Deposit
Agreements between the Escrow Agent and the Replacement Depositary.

"Deposit Make-Whole Premium" means, with respect to the distribution of unused
Deposits to holders of any Class of Certificates, as of any date of
determination, an amount equal to the excess, if any, of (a) the present value
of the excess of (i) the scheduled payment of principal and interest to maturity
of the Equipment Notes, assuming the maximum principal amount thereof (the
"Maximum Amount") minus any Non-Premium Amount applicable to such Class of
Certificates and, in the case of Class C Certificates only, the Par Redemption
Amount were issued, on each remaining Regular Distribution Date for such Class
under the Assumed Amortization Schedule over (ii) the scheduled payment of
principal and interest to maturity of the Equipment Notes actually acquired by
the Pass Through Trustee for such Class on each such Regular Distribution Date,
such present value computed by discounting such excess on a semiannual basis on
each Regular Distribution Date (assuming a 360-day year of twelve 30-day months)
using a discount rate equal to the Adjusted Treasury Yield over (b) the amount
of such unused Deposits to be distributed to the holders of such Certificates
minus any Non-Premium Amount applicable to such Class of Certificates and, in
the case of Class C Certificates only, the Par Redemption Amount (the remainder
of such subtraction, the "Net Deposits") plus accrued and unpaid interest on the
Net Deposits to but excluding such date of determination from and including the
preceding Regular Distribution Date (or if such date of determination precedes
the first Regular Distribution Date, the Issuance Date).

"Depositary" means ABN AMRO Bank N.V., a banking institution organized under the
laws of the Netherlands, acting through its Chicago branch and, from and after
the transfer of the Deposits to a Replacement Depositary, shall mean such
Replacement Depositary.
<PAGE>   35
                                                                               3

"Equipment Notes" means and includes any equipment notes issued under any
Indenture in the form specified in Section 2.01 thereof (as such form may be
varied pursuant to the terms of such Indenture) and any Equipment Note issued
under any Indenture in exchange for or replacement of any other Equipment Note.

"Escrow Agent" has the meaning set forth in the first paragraph of the Note
Purchase Agreement.

"Escrow and Paying Agent Agreement" has the meaning set forth in the fifth
recital to the Note Purchase Agreement.

"FAA" means the Federal Aviation Administration of the United States.

"Final Withdrawal" with respect to each Escrow and Paying Agent Agreement, has
the meaning set forth in Section 1.02 thereof.

"Financing Agreements" means, collectively, the Lease Financing Agreements and
the Owner Financing Agreements.

"Government Entity" means (a) any federal, state, provincial or similar
government, and any body, board, department, commission, court, tribunal,
authority, agency or other instrumentality of any such government or otherwise
exercising any executive, legislative, judicial, administrative or regulatory
functions of such government or (b) any other government entity having
jurisdiction over any matter contemplated by the Operative Agreements or
relating to the observance or performance of the obligations of any of the
parties to the Operative Agreements.

"H.15(519)" means the weekly statistical release designated as such, or any
successor publication, published by the Board of Governors of the Federal
Reserve System.

"Indentures" means, collectively, the Leased Aircraft Indentures and the Owned
Aircraft Indentures.

"Initial Purchasers" has the meaning set forth in the fourth recital to the Note
Purchase Agreement.

"Intercreditor Agreement" has the meaning set forth in the ninth recital to the
Note Purchase Agreement.

"Issuance Date" means the date of the original issuance of the Certificates.

"Law" means (a) any constitution, treaty, statute, law, decree, regulation,
order, rule or directive of any Government Entity, and (b) any judicial or
administrative interpretation or application of, or decision under, any of the
foregoing.

"Lease" means a Lease Agreement substantially in the form of Exhibit A-2 to the
Note Purchase Agreement.

"Lease Financing Agreements" means, collectively, the Aircraft Purchase
Agreement Assignment, the Leased Aircraft Participation Agreement, the Lease,
the Leased Aircraft
<PAGE>   36
                                                                               4

Indenture, the Equipment Notes issued thereunder and the Trust Agreement
relating to the financing of a Leased Aircraft.

"Leased Aircraft" means an Aircraft subject to a Lease.

"Leased Aircraft Indenture" means a Trust Indenture and Mortgage substantially
in the form of Exhibit A-3 to the Note Purchase Agreement.

"Leased Aircraft Participation Agreement" means a Participation Agreement
substantially in the form of Exhibit A-1 to the Note Purchase Agreement.

"Liquidity Facility" has the meaning set forth in the ninth recital to the Note
Purchase Agreement.

"Liquidity Provider" has the meaning set forth in the tenth recital to the Note
Purchase Agreement.

"Loan Trustee" means the "Mortgagee" as defined in the Financing Agreements.

"Mandatory Document Terms" means the terms set forth on Schedule V to the Note
Purchase Agreement.

"Mandatory Economic Terms" means the terms set forth on Schedule VI to the Note
Purchase Agreement.

"Manufacturer" means AVSA, S.A.R.L., solely in its capacity as manufacturer or
seller of Aircraft.

"Material Adverse Change" means, with respect to any Person, any event,
condition or circumstance that materially and adversely affects such Person 's
business or consolidated financial condition or its ability to observe or
perform its obligations, liabilities and agreements under the Operative
Agreements.

"Non-Premium Amount" means, with respect to any Class of Certificates, if any
Aircraft has not been delivered by the Manufacturer on or prior to the Delivery
Period Termination Date due to any reason not occasioned by the Company's fault
or negligence and no Substitute Aircraft has been provided in lieu of such
Aircraft, an amount equal to the maximum principal amount of Equipment Notes
with respect to such Aircraft that could have been issued and acquired by the
Pass Through Trust that issued such Class of Certificates in accordance with the
Mandatory Economic Terms.

"Note Holder" means at any time each registered holder of one or more Equipment
Notes.

"Note Purchase Agreement" means the Note Purchase Agreement to which this Annex
A is attached.

"Notice of Purchase Withdrawal" with respect to each Deposit Agreement, has the
meaning set forth in Section 2.3 thereof.
<PAGE>   37
                                                                               5

"Operative Agreements" means, collectively, the Pass Through Trust Agreements,
the Escrow and Paying Agent Agreements, the Deposit Agreements, the Liquidity
Facilities, the Policy Provider Agreement, the Policy, the Intercreditor
Agreement, the Registration Rights Agreements, the Trust Agreements, the
Equipment Notes, the Certificates and the Financing Agreements.

"Owned Aircraft Indenture" means a Trust Indenture and Mortgage substantially in
the form of Exhibit C-2 to the Note Purchase Agreement.

"Owned Aircraft Participation Agreement" means a Participation Agreement
substantially in the form of Exhibit C-1 to the Note Purchase Agreement.

"Owner Financing Agreements" means, collectively, the Owned Aircraft
Participation Agreement, the Owned Aircraft Indenture and the Equipment Notes
issued thereunder.

"Owner Participant" means, with respect to any Leased Aircraft, the Person named
as the Owner Participant in the Participation Agreement with respect to such
Leased Aircraft.

"Owner Trust" means with respect to any Leased Aircraft, the trust created by
the "Trust Agreement" referred to in the Leased Aircraft Indenture related
thereto.

"Owner Trustee" means with respect to any Leased Aircraft, the "Owner Trustee"
party to the "Trust Agreement" referred to in the Leased Aircraft Indenture
related thereto.

"Par Redemption Amount" means $5,000,000.

"Participation Agreements" means, collectively, the Leased Aircraft
Participation Agreements and the Owned Aircraft Participation Agreements.

"Pass Through Trust" has the meaning set forth in the third recital to the Note
Purchase Agreement.

"Pass Through Trust Agreement" has the meaning set forth in the third recital to
the Note Purchase Agreement.

"Pass Through Trustee" has the meaning set forth in the first paragraph of the
Note Purchase Agreement.

"Paying Agent" has the meaning set forth in the first paragraph of the Note
Purchase Agreement.

"Person" means any individual, firm, partnership, joint venture, trust, trustee,
Government Entity, organization, association, corporation, government agency,
committee, department, authority and other body, corporate or incorporate,
whether having distinct legal status or not, or any member of any of the same.

"Policy " has the meaning set forth in the tenth recital to the Note Purchase
Agreement.

"Policy Obligations" has the meaning specified in the Intercreditor Agreement.

<PAGE>   38
                                                                               6

"Policy Provider" has the meaning set forth in the tenth recital to the Note
Purchase Agreement.

"Policy Provider Agreement" has the meaning set forth in the tenth recital to
the Note Purchase Agreement.

"Qualified Owner Participant" means any bank, trust company, insurance company,
financial institution, limited liability company, partnership or corporation, in
each case with a combined capital and surplus or net worth of at least
$50,000,000.

"Rating Agencies" means, collectively, at any time, each nationally recognized
rating agency which shall have been requested to rate the Certificates and which
shall then be rating the Certificates. The initial Rating Agencies will be
Moody's Investors Service, Inc. and Standard & Poor's Rating Services, a
division of The McGraw-Hill Companies Inc.

"Rating Agency Confirmation" means, with respect to any Financing Agreement that
has been modified in any material respect from the forms thereof attached to the
Note Purchase Agreement, with respect to Substitute Aircraft or with respect to
a Special Structure, a written confirmation from each of the Rating Agencies
that the use of such Financing Agreement with such modifications or the
substituting of such Substitute Aircraft for an Aircraft or the utilization of
other financing agreements in connection with such Special Structure, whichever
of the foregoing shall in a particular case require Rating Agency Confirmation,
would not result in (i) a reduction of the rating for any Class of Certificates
below the then current rating for such Class of Certificates (without regard to
the Policy) or (ii) a withdrawal or suspension of the rating of any Class of
Certificates, in each case, without reference to the Policy.

"Register" means the register maintained pursuant to Sections 3.04 and 7.12 of
each Pass Through Trust Agreement.

"Registration Rights Agreement" means the Exchange and Registration Rights
Agreement dated as of the Issuance Date, among the Initial Purchasers, the Pass
Through Trustees and the Company, as amended, supplemented or otherwise modified
from time to time in accordance with its terms.

"Regular Distribution Dates" shall mean January 2 and July 2 of each year,
commencing January 2, 2000.

"Remaining Weighted Average Life" means, on a given date with respect to any
Equipment Note, the number of days equal to the quotient obtained by dividing
(a) the sum of each of the products obtained by multiplying (i) the amount of
each then remaining scheduled payment of principal of such Equipment Note by
(ii) the number of days from and including such determination date to but
excluding the date on which such payment of principal is scheduled to be made,
by (b) the then outstanding principal amount of such Equipment Note.

"Replacement Depositary" has the meaning set forth in Section 4(a)(vii) of the
Note Purchase Agreement.

"Replacement Deposit Agreement" means, for each Class of Certificates, a deposit
agreement substantially in the form of the replaced Deposit Agreement for such
Class of Certificates as
<PAGE>   39
                                                                               7

shall permit the Rating Agencies to confirm in writing their respective ratings
then in effect for such Class of Certificates (before the downgrading of such
ratings, if any, as a result of the downgrading of the Depositary and without
regard to the Policy).

"Scheduled Delivery Date" has the meaning set forth in Section 1(b) hereof.

"Section 1110" means 11 U.S.C. Section 1110 of the Bankruptcy Code or any
successor or analogous Section of the federal bankruptcy Law in effect from time
to time.

"Series C Equipment Notes" means Equipment Notes issued under an Indenture and
designated as "Series C" thereunder.

"Series D Equipment Notes" means Equipment Notes issued under an Indenture and
designated as "Series C" thereunder, if any.

"Series G Equipment Notes" means Equipment Notes issued under an Indenture and
designated as "Series G" thereunder.

"Special Structure" has the meaning set forth in Section 1(c) of the Note
Purchase Agreement.

"Subordination Agent" has the meaning set forth in the first paragraph of the
Note Purchase Agreement.

"Substitute Aircraft" has the meaning set forth in Section 1(f) of the Note
Purchase Agreement.

"Taxes" 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.

"Treasury Yield" means, as of any date of determination, with respect to any
Equipment Note (utilizing the Assumed Amortization Schedule applicable thereto),
the interest rate (expressed as a decimal and, in the case of United States
Treasury bills, converted to a bond equivalent yield) determined to be the per
annum rate equal to the semi-annual yield to maturity for United States Treasury
securities maturing on the Average Life Date (of such Equipment Note) and
trading in the public securities markets either as determined by interpolation
between the most recent weekly average yield to maturity for two series of
United States Treasury securities, trading in the public securities markets, (A)
one maturing as close as possible to, but earlier than, the Average Life Date
(of such Equipment Note) and (B) the other maturing as close as possible to, but
later than, the Average Life Date (of such Equipment Note), in each case as
published in the most recent H.15(519) or, if a weekly average yield to maturity
for United States Treasury securities maturing on the Average Life Date (of such
Equipment Note) is reported on the most recent H.15(519), such weekly average
yield to maturity as published in such H.15(519).
<PAGE>   40
                                                                               8

"Triggering Event" has the meaning assigned to such term in the Intercreditor
Agreement.

"Trust Agreement" means a Trust Agreement substantially in the form of Exhibit
A-5 to the Note Purchase Agreement.

"Unindemnified Taxes" has the meaning assigned to such term in the Intercreditor
Agreement.

"WTC" has the meaning set forth in the first paragraph of the Note Purchase
Agreement.
<PAGE>   41
                                 EXHIBIT A-1 to
                             Note Purchase Agreement

                 FORM OF LEASED AIRCRAFT PARTICIPATION AGREEMENT
<PAGE>   42
                                 EXHIBIT A-2 to
                             Note Purchase Agreement

                                  FORM OF LEASE
<PAGE>   43
                                 EXHIBIT A-3 to
                             Note Purchase Agreement

                        FORM OF LEASED AIRCRAFT INDENTURE
<PAGE>   44
                                 EXHIBIT A-4 to
                             Note Purchase Agreement

                 FORM OF AIRCRAFT PURCHASE AGREEMENT ASSIGNMENT
<PAGE>   45
                                 EXHIBIT A-5 to
                             Note Purchase Agreement

                     FORM OF LEASED AIRCRAFT TRUST AGREEMENT
<PAGE>   46
                                  EXHIBIT B to
                             Note Purchase Agreement

                             FORM OF DELIVERY NOTICE

                         Dated as of __________ __, ____

To each of the addressees listed

         in Schedule A hereto

                  Re:      Delivery Notice in accordance with Note Purchase
                           Agreement referred to below

Gentlemen:

         Reference is made to the Note Purchase Agreement dated as of September
21, 1999 among America West Airlines, Inc. (the "Company"), Wilmington Trust
Company, as Pass Through Trustee under each of the Pass Through Trust Agreements
(as defined therein) (the "Pass Through Trustee"), Wilmington Trust Company, as
Subordination Agent (the "Subordination Agent"), Wilmington Trust Company, as
Escrow Agent (the "Escrow Agent") and Wilmington Trust Company, as Paying Agent
(the "Paying Agent") (as in effect from time to time, the "Note Purchase
Agreement"). Unless otherwise defined herein, capitalized terms used herein
shall have the meanings set forth in the Note Purchase Agreement or, to the
extent not defined therein, the Intercreditor Agreement.

         Pursuant to Section 1(b) of the Note Purchase Agreement, the
undersigned hereby notifies you, in respect of the Airbus ___ aircraft with
manufacturer's serial number _______ (the "Aircraft"), of the following:

(1)      The Company has elected to treat the Aircraft as a
         [Leased](1)/[Owned](2) Aircraft;

(2)      The Scheduled Delivery Date of the Aircraft is __________ __, ____; and

(3)      The aggregate amount of each series of Equipment Notes to be issued,
         and purchased by the respective Pass Through Trustees, on the Scheduled
         Delivery Date, in connection with the financing of such Aircraft is as
         follows:

         (a)      the Class G Trustee shall purchase Series G Equipment Notes in
                  the amount of $__________; and

         (b)      the Class C Trustee shall purchase Series C Equipment Notes in
                  the amount of $__________.

------------------------
1   To be inserted in the case of a Leased Aircraft.

2   To be inserted in the case of an Owned Aircraft.
<PAGE>   47
                                                                               2

         The Company hereby instructs the Class G Trustee to (i) execute a
Withdrawal Certificate in the form of Annex A hereto dated _____ __, ____ [a
date which is no later than one Business Day prior to the Scheduled Delivery
Date] and attach thereto a Notice of Purchase Withdrawal dated such date
completed as set forth on Exhibit A hereto and (ii) deliver such Withdrawal
Certificate and Notice of Purchase Withdrawal to the applicable Escrow Agent.

         The Company hereby instructs the Class C Trustee to (i) execute a
Withdrawal Certificate in the form of Annex A hereto dated _____ __, ____ [a
date which is no later than one Business Day prior to the Scheduled Delivery
Date] and attach thereto a Notice of Purchase Withdrawal dated such date
completed as set forth on Exhibit B hereto and (ii) deliver such Withdrawal
Certificate and Notice of Purchase Withdrawal to the applicable Escrow Agent.

         The Company hereby instructs each Pass Through Trustee to (i) purchase
Equipment Notes of a series and in an amount set forth opposite such Pass
Through Trustee in clause (3) above with a portion of the proceeds of the
withdrawals of Deposits referred to in the applicable Notice of Purchase
Withdrawal referred to above and (ii) re-deposit with the Depositary the excess,
if any, of the amount so withdrawn over the purchase price of such Equipment
Notes.

         The Company hereby instructs each Pass Through Trustee to (a) enter
into the Participation Agreement dated as of _____ __, ____ among the Company,
as [Lessee](3)/[Owner](4), the Subordination Agent, the Pass Through Trustee,
___________________, as Mortgagee [and Loan Participant, _____________________,
as Owner Trustee and _________, as Owner Participant](5), (b) perform its
obligations thereunder and (c) deliver such certificates, documents and legal
opinions relating to such Pass Through Trustee as required thereby.

         [The Company hereby certifies that the Owner Participant with respect
to the Aircraft is (a) not an Affiliate of the Company and (b) a [Qualified
Owner Participant/person whose obligations under the Owner Participant
Agreements (as defined in the Participation Agreement) are guaranteed by a
Qualified Owner Participant].](6)

Yours faithfully,

America West Airlines, Inc.

By:
   -------------------------------
   Name:
   Title:



------------------------
3   To be inserted in the case of a Leased Aircraft.

4   To be inserted in the case of an Owned Aircraft.

5   To be inserted in the case of a Leased Aircraft.

6   To be inserted in the case of a Leased Aircraft.
<PAGE>   48
                                   SCHEDULE A


Wilmington Trust Company, as
   Pass Through Trustee, Subordination
   Agent, Escrow Agent and Paying Agent
Rodney Square North
1100 North Market Street
Wilmington, Delaware 19890
Attention: Corporate Trust
           Administration
Facsimile: (302) 651-8882

Standard & Poor's Ratings Services
55 Water Street, 35th Floor
New York, New York  10041
Attention:  Betsy R. Snyder
Facsimile:  (212) 438-7811

Moody's Investors Service, Inc.
99 Church Street
New York, New York  10007
Attention:  Bob Jankowitz
Facsimile:  (212) 553-4600

Ambac Assurance Corporation
One State Street Plaza
New York, New York  10004
Attention:  David Nemschoff
Facsimile:  (212) 208-3113
<PAGE>   49
                                                                         ANNEX A

                             WITHDRAWAL CERTIFICATE

                                  (Class __)(7)

Wilmington Trust Company,
as Escrow Agent

Dear Sirs:

                  Reference is made to the Escrow and Paying Agent Agreement,
dated as of September 21, 1999 (the "Agreement"). We hereby certify to you that
the conditions to the obligations of the undersigned to execute a Participation
Agreement pursuant to the Note Purchase Agreement have been satisfied. Pursuant
to Section 1.02(c) of the Agreement, please execute the attached Notice of
Withdrawal and immediately transmit by facsimile to the Depositary, at (312)
606-8428.

                                       Very truly yours,

                                       WILMINGTON TRUST COMPANY, not in its
                                       individual capacity by solely as Pass
                                       Through Trustee


                                       By:_____________________________________
                                          Name:
                                          Title:

Dated: _______ __, ____



------------------------
7   Insert letter of appropriate class of Certificates.
<PAGE>   50
                                                                       EXHIBIT A

                          NOTICE OF PURCHASE WITHDRAWAL

ABN AMRO BANK N.V.,
  Chicago Branch
135 South LaSalle Street
Chicago, Illinois  60603
Attention:  Vice President - Aerospace
Telecopier: (312) 606-8428

Gentlemen:

                  Reference is made to (i) the Deposit Agreement (Class G) dated
as of September 21, 1999 (the "Deposit Agreement") between Wilmington Trust
Company, as Escrow Agent, and ABN AMRO Bank N.V., Chicago Branch, as Depositary
(the "Depositary").

                  In accordance with Section 2.3(a) of the Deposit Agreement,
the undersigned hereby requests the withdrawal of the entire amount of the
Deposit, $_______, Account No. ____________.

                  The undersigned hereby directs the Depositary to pay the
proceeds of the Deposit to [________________, Account No. _____, Reference:
_________] on _________ __, ____, upon the telephonic request of a
representative of the Pass Through Trustee.

                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent


                                       By:_____________________________________
                                          Name:
                                          Title:

Dated: _______ __, ____
<PAGE>   51
                                                                       EXHIBIT B

                          NOTICE OF PURCHASE WITHDRAWAL

ABN AMRO BANK N.V.,
  Chicago Branch
135 South LaSalle Street
Chicago, Illinois  60603
Attention:  Vice President - Aerospace
Telecopier: (312) 606-8428

Gentlemen:

                  Reference is made to (i) the Deposit Agreement (Class C) dated
as of September 21, 1999 (the "Deposit Agreement") between Wilmington Trust
Company, as Escrow Agent, and ABN AMRO Bank N.V., Chicago Branch, as Depositary
(the "Depositary").

                  In accordance with Section 2.3(a) of the Deposit Agreement,
the undersigned hereby requests the withdrawal of the entire amount of the
Deposit, $_______, Account No. ____________.

                  The undersigned hereby directs the Depositary to pay the
proceeds of the Deposit to [________________, Account No. _____, Reference:
_________] on _________ __, ____, upon the telephonic request of a
representative of the Pass Through Trustee.

                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent


                                       By:_____________________________________
                                             Name:
                                             Title:

Dated: _______ __, ____
<PAGE>   52
                                 EXHIBIT C-1 to
                             Note Purchase Agreement

                 FORM OF OWNED AIRCRAFT PARTICIPATION AGREEMENT
<PAGE>   53
                                 EXHIBIT C-2 to
                             Note Purchase Agreement

                        FORM OF OWNED AIRCRAFT INDENTURE
<PAGE>   54
                                  EXHIBIT D to
                             Note Purchase Agreement

         ADDITIONAL SUBORDINATION PROVISION FOR SERIES D EQUIPMENT NOTES



                  Subordination.



                  (a)      As between the Note Holders, this Trust Indenture
                           shall be a subordination agreement for purposes of
                           Section 510 of the United States Bankruptcy Code, as
                           amended, from time to time.

                  (b)      If any Note Holder receives any payment in respect of
                           any obligations owing hereunder, which is
                           subsequently invalidated, declared preferential, set
                           aside and/or required to be repaid to a trustee,
                           receiver or other party, then, to the extent of such
                           payment, such obligations intended to be satisfied
                           shall be revived and continue in full force and
                           effect as if such payment had not been received.

                  (c)      Each of the Note Holders may take any of the
                           following actions without impairing its rights under
                           this Trust Indenture:

                           (i)      obtain a Lien on any property to secure any
                                    amounts owing to it hereunder,

                           (ii)     obtain the primary or secondary obligation
                                    of any other obligor with respect to any
                                    amounts owing to it hereunder,

                           (iii)    renew, extend, increase, alter or exchange
                                    any amounts owing to it hereunder, or
                                    release or compromise any obligation of any
                                    obligor with respect thereto,

                           (iv)     refrain from exercising any right or remedy,
                                    or delay in exercising such right or remedy,
                                    which it may have, or

                           (v)      take any other action which might discharge
                                    a subordinated party or a surety under
                                    applicable law;

                           provided, however, that the taking of any such
                           actions by any of the Note Holders shall not
                           prejudice the rights or adversely affect the
                           obligations of any other party under this Trust
                           Indenture.