<PAGE>   1
                                                                    Exhibit 4.12










                                DEPOSIT AGREEMENT
                                    (Class G)

                         Dated as of September 21, 1999


                                     between


                            WILMINGTON TRUST COMPANY

                                 as Escrow Agent


                                       and


                               ABN AMRO BANK N.V.,
                                 Chicago Branch

                                  as Depositary
<PAGE>   2
         DEPOSIT AGREEMENT (Class G) dated as of September 21, 1999 (as amended,
modified or supplemented from time to time, this "Agreement") between WILMINGTON
TRUST COMPANY, a Delaware banking corporation, as Escrow Agent under the Escrow
and Paying Agent Agreement referred to below (in such capacity, together with
its successors in such capacity, the "Escrow Agent"), and ABN AMRO BANK N.V., a
bank organized under the laws of the Netherlands, acting through its Chicago
branch, as depositary bank (the "Depositary").

                               W I T N E S S E T H

         WHEREAS, America West Airlines, Inc. ("America West") and Wilmington
Trust Company, not in its individual capacity except as otherwise expressly
provided therein, but solely as trustee (in such capacity, together with its
successors in such capacity, the "Pass Through Trustee") have entered into a
Pass Through Trust Agreement dated as of September 21, 1999 (as amended,
modified or supplemented from time to time in accordance with the terms thereof,
the "Pass Through Trust Agreement") relating to America West Airlines Pass
Through Trust 1999-1G-O pursuant to which the America West Airlines Pass Through
Trust, Series 1999-1G-O Certificates referred to therein (the "Certificates")
are being issued;

         WHEREAS, America West and Morgan Stanley & Co. Incorporated, Donaldson,
Lufkin & Jenrette Securities Corporation, Merrill Lynch, Pierce, Fenner & Smith
Incorporated and Salomon Smith Barney Inc. (collectively, the "Initial
Purchasers" and, together with their respective transferees and assigns as
registered owners of the Certificates, the "Investors") have entered into a
Purchase Agreement dated as of September 14, 1999 pursuant to which the Pass
Through Trustee will issue and sell the Certificates to the Initial Purchasers
(the net proceeds of such sale being herein referred to as the "Net Proceeds");

         WHEREAS, America West, the Pass Through Trustee, certain other pass
through trustees and certain other persons concurrently herewith are entering
into the Note Purchase Agreement, dated as of the date hereof (the "Note
Purchase Agreement"), pursuant to which the Pass Through Trustee has agreed to
acquire from time to time on or prior to the Delivery Period Termination Date
(as defined in the Note Purchase Agreement) equipment notes (the "Equipment
Notes") issued to finance or refinance the acquisition of aircraft by America
West, as lessee or as owner, utilizing a portion of the Net Proceeds;

         WHEREAS, the Escrow Agent, the Initial Purchasers, the Pass Through
Trustee and Wilmington Trust Company, as paying agent for the Escrow Agent (in
such capacity, together with its successors in such capacity, the "Paying
Agent") concurrently herewith are entering into an Escrow and Paying Agent
Agreement, dated as of the date hereof (as amended, modified or supplemented
from time to time in accordance with the terms thereof, the "Escrow and Paying
Agent Agreement"); and

         WHEREAS, the Initial Purchasers and the Pass Through Trustee intend
that the Net Proceeds be held in escrow by the Escrow Agent on behalf of the
Investors pursuant to the Escrow and Paying Agent Agreement, subject to
withdrawal upon request of and proper
<PAGE>   3
certification by the Pass Through Trustee for the purpose of purchasing
Equipment Notes, and that pending such withdrawal the Net Proceeds be deposited
by the Escrow Agent with the Depositary pursuant to this Agreement, which
provides for the Depositary to pay interest for distribution to the Investors
and to establish accounts from which the Escrow Agent shall make withdrawals
upon request of and proper certification by the Pass Through Trustee.

         NOW, THEREFORE, in consideration of the obligations contained herein,
and for other good and valuable consideration, the receipt and sufficiency of
which is hereby acknowledged, the parties hereto hereby agree as follows:

         SECTION 1.1 Acceptance of Depositary. The Depositary hereby agrees to
act as depositary bank as provided herein and in connection therewith to accept
all amounts to be delivered to or held by the Depositary pursuant to the terms
of this Agreement. The Depositary further agrees to hold, maintain and safeguard
the Deposits and the Accounts (as defined below) during the term of this
Agreement in accordance with the provisions of this Agreement. The Escrow Agent
shall not have any right to withdraw, assign or otherwise transfer moneys held
in the Accounts except as permitted by this Agreement.

         SECTION 1.2 Establishment of Accounts. The Escrow Agent hereby
instructs the Depositary, and the Depositary agrees, to establish the separate
deposit accounts listed on Schedule I hereto and to establish such additional
separate deposit accounts as may be required in connection with the deposits
contemplated by Section 1.6 hereof (each, an "Account" and collectively, the
"Accounts"), each in the name of the Escrow Agent and all on the terms and
conditions set forth in this Agreement.

         SECTION 1.3 Deposits. The Escrow Agent shall direct the Initial
Purchasers to deposit with the Depositary on the date of this Agreement (the
"Deposit Date") in Federal (same day) funds by wire transfer to: Federal Reserve
Bank, New York, ABN NY ABA #026009580, Account: Chicago Treasury, Reference:
America West Deposit, and the Depositary shall accept from the Initial
Purchasers, on behalf of the Escrow Agent, the sum of US$233,668,000. Upon
acceptance of such sum, the Depositary shall (i) establish each of the deposits
specified in Schedule I hereto maturing on the respective dates set forth
therein (including any deposit made pursuant to Section 1.6 hereof,
individually, a "Deposit" and, collectively, the "Deposits") and (ii) credit
each Deposit to the related Account as set forth therein. No amount shall be
deposited in any Account other than the related Deposit.

         SECTION 1.4 Interest. (a) Each Deposit shall bear interest from and
including the date of deposit to but excluding the date of withdrawal at the
rate of 7.93% per annum (computed on the basis of a year of twelve 30-day
months) payable to the Paying Agent on behalf of the Escrow Agent semi-annually
in arrears on each January 2 and July 2 commencing on January 2, 2000 (each, an
"Interest Payment Date") and, as provided in Section 1.5(b) hereof, on the date
of the Final Withdrawal (as defined below), all in accordance with the terms of
this Agreement (whether or not any such Deposit is withdrawn on an Interest
Payment Date). Interest accrued on any Deposit that is withdrawn pursuant to a
Notice of Purchase Withdrawal (as defined below) shall be paid on the next
Interest Payment Date, notwithstanding any intervening Final

                                       2
<PAGE>   4
Withdrawal (as defined below) of all of the remaining Deposits (any such
Deposits consisting of unpaid interest only and remaining after a Final
Withdrawal may be referred to as the "Carryover Deposits"). In addition,
interest accrued on any Deposit that is withdrawn pursuant to a Notice of
Replacement Withdrawal (as defined below) but not paid on the date of the Final
Withdrawal shall be paid on the next Interest Payment Date.

                  (b) The parties hereto further acknowledge and agree that upon
any increase in the rate of interest on the Certificates (such increase referred
to as a "Rate Increase") pursuant to the terms of the Registration Rights
Agreement, the rate of interest borne by each Deposit in accordance with Section
1.4(a) above shall increase by the amount of such Rate Increase, and upon any
subsequent decrease in the rate of interest on the Equipment Notes (such
decrease referred to as a "Rate Decrease") pursuant to the terms of the
Registration Rights Agreement, the rate of interest borne by such Deposit shall
decrease by the amount of such Rate Decrease. For the purposes of this Section
1.4(b), "Registration Rights Agreement" means the Exchange and Registration
Rights Agreement dated the date hereof among America West, the Pass Through
Trustee, certain other pass through trustees and the Initial Purchasers.

         SECTION 1.5 Withdrawals. (a) On and after the date seven days after the
establishment of any Deposit, the Escrow Agent may, by providing at least one
Business Day's prior notice of withdrawal to the Depositary in the form of
Exhibit A hereto (a "Notice of Purchase Withdrawal"), withdraw not less than the
entire principal balance of such Deposit, except that at any time prior to the
actual withdrawal of such Deposit, the Escrow Agent or the Pass Through Trustee
may, by notice to the Depositary, cancel such withdrawal (including on the
scheduled date therefor), and thereafter such Deposit shall continue to be
maintained by the Depositary in accordance with the original terms thereof.
Following such withdrawal the balance in the related Account shall be zero and
the Depositary shall, subject to the Depositary's payment obligation pursuant to
the last sentence of Section 1.4(a) hereof, close such Account. As used herein,
"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, Chicago, Illinois, Phoenix, Arizona or Wilmington, Delaware.
Notwithstanding the foregoing, 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 of the Note Purchase Agreement, the Notice of
Purchase Withdrawal may be delivered to the Depositary on such scheduled
delivery date for withdrawals on that day. The Depositary reserves the right,
upon at least 14 days' prior written notice to America West, the Escrow Agent
and the Pass Through Trustee, to require seven days' notice for any withdrawal.

                  (b) (i) The Escrow Agent may, subject to Section 1.02(d) of
the Escrow and Paying Agent Agreement, by providing at least 15 days' prior
notice of withdrawal to the Depositary in the form of Exhibit B hereto (a
"Notice of Final Withdrawal"), withdraw the entire amount of all of the
remaining Deposits together with the payment by the Depositary of all accrued
and unpaid interest on such Deposits to but excluding the specified date of
withdrawal (a "Final Withdrawal"), on such date as shall be specified in such
Notice of Final Withdrawal. If a Notice of Final Withdrawal has not been given
to the Depositary on or before September 6, 2000

                                       3
<PAGE>   5
and there are unwithdrawn Deposits on such date, the Depositary shall pay the
amount of the Final Withdrawal to the Paying Agent on September 27, 2000.

                  (ii) The Escrow Agent may, by providing at least 15 days'
prior notice of withdrawal to the Depositary in the form of Exhibit C hereto (a
"Notice of Replacement Withdrawal"), withdraw the entire amount of all Deposits
then held by the Depositary together with, if specified in such Notice of
Replacement Withdrawal, the payment by the Depositary of all accrued and unpaid
interest on such Deposits to but excluding the specified date of withdrawal (a
"Replacement Withdrawal"), on such date as shall be specified in such Notice of
Replacement Withdrawal.

                  (c) If the Depositary receives a duly completed Notice of
Purchase Withdrawal or Notice of Final Withdrawal or Notice of Replacement
Withdrawal (each, a "Withdrawal Notice") complying with the provisions of this
Agreement, it shall make the payments specified therein in accordance with the
provisions of this Agreement. If such complying Withdrawal Notice is received by
the Depositary no later than 3:00 p.m. on a Business Day, the Depositary shall
make the payments requested in such Withdrawal Notice no later than 11:00 a.m.
on the next succeeding Business Day or such later day specified in such
Withdrawal Notice, and if such complying Withdrawal Notice is received by the
Depositary after 3:00 p.m. on a Business Day, the Depositary shall make the
payments requested in such Withdrawal Notice no later than 11:00 a.m. on the
second Business Day next following such Business Day.

         SECTION 1.6 Other Accounts. On the date of withdrawal of any Deposit
pursuant to a Notice of Purchase Withdrawal, the Escrow Agent, or the Pass
Through Trustee on behalf of the Escrow Agent, shall be entitled to re-deposit
with the Depositary any portion thereof and the Depositary shall accept the same
for deposit hereunder. Any sums so received for deposit shall be established as
a new Deposit and credited to a new Account, all as more fully provided in
Section 1.3 hereof, and thereafter the provisions of this Agreement shall apply
thereto as fully and with the same force and effect as if such Deposit had been
established on the Deposit Date except that (i) such Deposit may not be
withdrawn prior to the date seven days after the establishment thereof and (ii)
such Deposit shall mature on September 27, 2000 and bear interest as provided in
Section 1.4. The Depositary shall promptly give notice to the Escrow Agent of
receipt of each such re-deposit and the account number assigned thereto.

         SECTION 2. Termination. This Agreement shall terminate on the fifth
Business Day after the later of the date on which (i) all of the Deposits shall
have been withdrawn and paid as provided herein without any re-deposit and (ii)
all accrued and unpaid interest on the Deposits shall have been paid as provided
herein, but in no event prior to the date on which the Depositary shall have
performed in full its obligations hereunder. For the avoidance of doubt, the
obligations of the Depositary under the last two sentences of Section 1.4(a)
hereof shall remain in full force and effect notwithstanding the execution and
delivery of a replacement Deposit Agreement in accordance with Section 4(a)(vii)
of the Note Purchase Agreement.

         SECTION 3. Payments. All payments (including, without limitation, those
payments made in respect of Taxes (as defined and provided for below)) made by
the Depositary hereunder

                                       4
<PAGE>   6
shall be paid in United States Dollars and immediately available funds by wire
transfer (i) in the case of accrued interest on the Deposits payable under
Section 1.4 hereof or any Final Withdrawal, directly to the Paying Agent at
Wilmington Trust Company, Wilmington, Delaware, ABA# 031-100-092, for credit to
the account of America West 1999-1, Account No. 49184-0, Attention: Rosemary
Pantano, Telephone No. (302) 427-4805, Reference: America West 1999-1G, or to
such other account as the Paying Agent may direct from time to time in writing
to the Depositary and the Escrow Agent and (ii) in the case of any withdrawal of
one or more Deposits pursuant to a Notice of Purchase Withdrawal or Notice of
Replacement Withdrawal, directly to or as directed by the Pass Through Trustee
as specified and in the manner provided in such Notice of Purchase Withdrawal or
Notice of Replacement Withdrawal. The Depositary hereby waives any and all
rights of set-off, combination of accounts, right of retention or similar right
(whether arising under applicable law, contract or otherwise) it may have
against the Deposits howsoever arising. All payments on or in respect of each
Deposit shall be made free and clear of and without reduction for or on account
of any and all taxes, levies or other impositions or charges (collectively,
"Taxes"). However, if the Depositary or the Paying Agent (pursuant to Section
2.04 of the Escrow and Paying Agent Agreement) shall be required by law to
deduct or withhold any Taxes from or in respect of any sum payable hereunder,
the Depositary shall (i) make such deductions or withholding, (ii) pay the full
amount deducted or withheld (including in respect of such additional amounts) to
the competent taxation authority and (iii) if the Taxes required to be deducted
or withheld are imposed by the Netherlands or any political subdivision thereof,
pay such additional amounts as may be necessary in order that the actual amount
received by the designated recipient of such sum under this Agreement or the
Escrow and Paying Agent Agreement after such deduction or withholding equals the
sum it would have received had no such deduction or withholding been required.
If the date on which any payment due on any Deposit would otherwise fall on a
day which is not a Business Day, such payment shall be made on the next
succeeding Business Day, and no additional interest shall accrue in respect of
such extension.

         SECTION 4. Representation and Warranties. The Depositary hereby
represents and warrants to America West, the Escrow Agent, the Pass Through
Trustee, the Initial Purchasers and the Paying Agent that:

                  (1) it is a bank duly organized and validly existing in good
standing under the laws of its jurisdiction of organization and is duly
qualified to conduct banking business in the State of Illinois through its
Chicago branch;

                  (2) it has full power, authority and legal right to conduct
its business and operations as currently conducted and to enter into and perform
its obligations under this Agreement;

                  (3) the execution, delivery and performance of this Agreement
have been duly authorized by all necessary corporate action on the part of it
and do not require any stockholder approval, or approval or consent of any
trustee or holder of any indebtedness or obligations of it, and such document
has been duly executed and delivered by it and constitutes its legal, valid and
binding obligations enforceable against it in accordance with the terms hereof;

                                       5
<PAGE>   7
                  (4) no authorization, consent or approval of or other action
by, and no notice to or filing with, any United States federal or state
governmental authority or regulatory body is required for the execution,
delivery or performance by it of this Agreement;

                  (5) neither the execution, delivery or performance by it of
this Agreement, nor compliance with the terms and provisions hereof, conflicts
or will conflict with or results or will result in a breach or violation of any
of the terms, conditions or provisions of, or will require any consent or
approval under, any law, governmental rule or regulation or the charter
documents, as amended, or bylaws, as amended, of it or any similar instrument
binding on it or any order, writ, injunction or decree of any court or
governmental authority against it or by which it or any of its properties is
bound or any indenture, mortgage or contract or other agreement or instrument to
which it is a party or by which it or any of its properties is bound, or
constitutes or will constitute a default thereunder or results or will result in
the imposition of any lien upon any of its properties; and

                  (6) there are no pending or, to its knowledge, threatened
actions, suits, investigations or proceedings (whether or not purportedly on
behalf of it) against or affecting it or any of its property before or by any
court or administrative agency which, if adversely determined, (i) would
adversely affect the ability of it to perform its obligations under this
Agreement or (ii) would call into question or challenge the validity of this
Agreement or the enforceability hereof in accordance with the terms hereof, nor
is the Depositary in default with respect to any order of any court,
governmental authority, arbitration board or administrative agency so as to
adversely affect its ability to perform its obligations under this Agreement.

         SECTION 5. Transfer. Neither party hereto shall be entitled to assign
or otherwise transfer this Agreement (or any interest herein) other than (in the
case of the Escrow Agent) to a successor escrow agent under the Escrow and
Paying Agent Agreement, and any purported assignment in violation thereof shall
be void. This Agreement shall be binding upon the parties hereto and their
respective successors and (in the case of the Escrow Agent) permitted assigns.
Upon the occurrence of the Transfer (as defined below) contemplated by the
Assignment and Assumption Agreement (as defined below), the Pass Through Trustee
shall (without further act) be deemed to have transferred all of its right,
title and interest in and to this Agreement to the trustee of the Successor
Trust (as defined below) and, thereafter, the trustee of the Successor Trust
shall be deemed to be the "Pass Through Trustee" hereunder with the rights of
the "Pass Through Trustee" hereunder, and each reference herein to "America West
Airlines Pass Through Trust 1999-1G-O" shall be deemed to be a reference to
"America West Airlines Pass Through Trust 1999-1G-S". The Escrow Agent and the
Depositary hereby acknowledge and consent to the Transfer contemplated by the
Assignment and Assumption Agreement. For the purposes of this Section 6,
"Transfer" means the transfer contemplated by the Assignment and Assumption
Agreement; "Assignment and Assumption Agreement" means the Assignment and
Assumption Agreement to be entered into between the Pass Through Trustee and the
trustee of the Successor Trust, substantially in the form of Exhibit D to the
Pass Through Trust Agreement; and "Successor Trust" means the America West
Airlines Pass Through Trust 1999-1G-S.

                                       6
<PAGE>   8
         SECTION 6. Amendment, Etc. This Agreement may not be amended, waived or
otherwise modified except by an instrument in writing signed by the party
against whom the amendment, waiver or other modification is sought to be
enforced and by the Pass Through Trustee.

         SECTION 7. Notices. Unless otherwise expressly provided herein, any
notice or other communication under this Agreement shall be in writing
(including by facsimile) and shall be deemed to be given and effective upon
receipt thereof (or, if received after normal business hours, the next open of
business on a Business Day). All notices shall be sent to (x) in the case of the
Depositary, ABN AMRO BANK N.V., 135 South LaSalle Street, Chicago, Illinois
60603, Attention: Vice President - Aerospace (Telecopier: 312-606-8428), with a
copy to ABN AMRO Bank N.V., Chicago Branch, 181 W. Madison Street, Chicago,
Illinois 60602, Attention: Money Market Desk (Telecopier: 312-904-9107) or (y)
in the case of the Escrow Agent, Wilmington Trust Company, 1100 North Market
Street, Wilmington, Delaware 19890, Attention: Corporate Trust Administration
(Telecopier: (302) 651-8882), in each case, with a copy to the Pass Through
Trustee, Wilmington Trust Company, 1100 North Market Street, Wilmington,
Delaware 19890, Attention: Corporate Trust Administration (Telecopier: (302)
651-8882) and to America West, America West Airlines, Inc., 4000 East Sky Harbor
Boulevard, Phoenix, Arizona 95043, Attention: Senior Vice President-Legal
Affairs (Telecopier: (602) 693-5904) (or at such other address as any such party
may specify from time to time in a written notice to the parties hereto). On or
prior to the execution of this Agreement, the Escrow Agent has delivered to the
Depositary a certificate containing specimen signatures of the representatives
of the Escrow Agent who are authorized to give notices and instructions with
respect to this Agreement. The Depositary may conclusively rely on such
certificate until the Depositary receives written notice from the Escrow Agent
to the contrary.

         SECTION 8. Obligations Unconditional. The Depositary hereby
acknowledges and agrees that its obligation to repay each Deposit together with
interest thereon as provided herein is absolute, irrevocable and unconditional
and constitutes a full recourse obligation of the Depositary enforceable against
it to the full extent of all of its assets and properties.

         SECTION 9. Entire Agreement. This Agreement (including all attachments
hereto) sets forth all of the promises, covenants, agreements, conditions and
understandings between the Depositary and the Escrow Agent with respect to the
subject matter hereof and supersedes all prior and contemporaneous agreements
and undertakings, inducements or conditions, express or implied, oral or
written.

         SECTION 10. Governing Law. This Agreement, and the rights and
obligations of the Depositary and the Escrow Agent with respect to the Deposits,
shall be governed by, and construed in accordance with, the law of the State of
New York.

         SECTION 11. Waiver of Jury Trial Right. EACH OF THE DEPOSITARY AND THE
ESCROW AGENT ACKNOWLEDGES AND ACCEPTS THAT IN ANY SUIT, ACTION OR PROCEEDING
ARISING OUT OF OR RELATING TO THIS AGREEMENT SUCH PARTY IRREVOCABLY WAIVES ITS
RIGHT TO A TRIAL BY JURY.

                                       7
<PAGE>   9
         SECTION 12. Counterparts. This Agreement may be executed in one or more
counterparts, all of which taken together shall constitute one instrument.

         SECTION 13. Head Office Obligation. ABN AMRO Bank N.V. hereby agrees
that the obligations of the Depositary hereunder are also the obligations of ABN
AMRO Bank N.V.'s Head Office in the Netherlands. Accordingly, any beneficiary of
this Agreement will be able to proceed directly against ABN AMRO Bank N.V.'s
Head Office in the Netherlands if ABN AMRO Bank N.V.'s Chicago branch defaults
in its obligation to such beneficiary under this Agreement.

         SECTION 14. Special Deposits. Notwithstanding anything to the contrary
in this Agreement, (i) the first Deposit listed on Schedule I hereto and the
second Deposit listed on Schedule I hereto (collectively, the "Special
Deposits") shall not bear interest, but otherwise shall be treated as Deposits
for all purposes of this Agreement and (ii) the Escrow Agent shall withdraw both
Special Deposits on the date hereof and may re-deposit all or any portion of
each such Special Deposit on the date hereof in accordance with Section 1.6
hereof, and, for the avoidance of doubt, any such re-deposited sum shall no
longer constitute a "Special Deposit" hereunder but shall be treated as a new
Deposit for all purposes hereunder and shall bear interest as provided in
Section 1.4 hereof.


                                      * * *

                                       8
<PAGE>   10
                  IN WITNESS WHEREOF, the Escrow Agent and the Depositary have
caused this Deposit Agreement to be duly executed as of the day and year first
above written.



                                       WILMINGTON TRUST COMPANY,
                                          as Escrow Agent


                                       By:   /s/ James P. Lawler
                                          -------------------------------------
                                          Name:   James P. Lawler
                                               --------------------------------
                                          Title:  Vice President
                                               --------------------------------



                                       ABN AMRO BANK N.V., CHICAGO BRANCH, as
                                       Depositary



                                       By:   /s/ Claudia C. Heldring
                                          -------------------------------------
                                          Name:   Claudia C. Heldring
                                               --------------------------------
                                          Title:  Vice President
                                                -------------------------------



                                       By:   /s/ Carla S. Waggoner
                                          -------------------------------------
                                          Name:   Carla S. Waggoner
                                               --------------------------------
                                          Title:  Assistant Vice President
                                                -------------------------------
<PAGE>   11
                                   Schedule I

                              Schedule of Deposits
                                    (Class G)


<TABLE>
<CAPTION>
Date                            Deposit Amount               Account No.                  Maturity Date
----                            --------------               -----------                  -------------
<S>                             <C>                          <C>                          <C>
9/21/99                         21,295,200.00                00454176-807G                September 27, 2000
9/21/99                         25,183,014.44                00454176-654G                September 27, 2000
9/21/99                         21,321,800.00                616044                       September 27, 2000
9/21/99                         25,238,082.06                616070                       September 27, 2000
9/21/99                         21,420,600.00                616079                       September 27, 2000
9/21/99                         25,427,401.81                616081                       September 27, 2000
9/21/99                         25,427.401.81                616108                       September 27, 2000
9/21/99                         21,447,200.00                616112                       September 27, 2000
9/21/99                         21,422,245.69                616153                       September 27, 2000
9/21/99                         25,485,054.19                616161                       September 27, 2000
</TABLE>
<PAGE>   12
                                    EXHIBIT A

                          NOTICE OF PURCHASE WITHDRAWAL



ABN AMRO BANK N.V.
135 South LaSalle Street
Chicago, Illinois  60603
Attention: Lukas van der Hoef
Telecopier: (312) 606-8428

Gentlemen:

         Reference is made to 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 1.5(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
_________ __, 199_, upon the telephonic request of a representative of the Pass
Through Trustee.


                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent



                                       By:_____________________________________

                                          Name:________________________________

                                          Title:_______________________________


Dated: _________, 199_
<PAGE>   13
                                    EXHIBIT B

                           NOTICE OF FINAL WITHDRAWAL

ABN AMRO BANK N.V.
135 South LaSalle Street
Chicago, Illinois  60603
Attention: Lukas van der Hoef
Telecopier: (312) 606-8428

Gentlemen:

         Reference is made to 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 1.5(b) of the Deposit Agreement, the
undersigned hereby requests the withdrawal of the entire amount of all Deposits
for payment on _______________, 199__.

         The undersigned hereby directs the Depositary to pay the proceeds of
the Deposits [and accrued interest thereon] to the Paying Agent at
__________________________, ABA# _____________, Account No. _____________,
Reference: America West 1999-1.


                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent



                                       By:_____________________________________

                                          Name:________________________________

                                          Title:_____________________________


Dated: _________, 199_
<PAGE>   14
                                    EXHIBIT C

                        NOTICE OF REPLACEMENT WITHDRAWAL

ABN AMRO BANK N.V.
135 South LaSalle Street
Chicago, Illinois  60603
Attention: Lukas van der Hoef
Telecopier: (312) 606-8428

Gentlemen:

         Reference is made to 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 1.5(b)(ii) of the Deposit Agreement, the
undersigned hereby requests the withdrawal of the entire amount of all Deposits
for payment on _______________, 199__.

         The undersigned hereby directs the Depositary to pay the proceeds of
the Deposits to [________________] at __________________________, ABA#
_____________, Account No. _____________, Reference: America West 1999-1 [and to
pay accrued interest thereon to the Paying Agent at ___________, ABA
#___________, Acct. No. ___________, Reference: America West ___ 1999-1]1. [The
undersigned further directs the Depositary to pay the accrued interest on the
Deposits to the Paying Agent on _______, __ (the next Interest Payment Date) at
ABA # ___________, Account No. __________, Reference: America West 1999-1.]2


                                       WILMINGTON TRUST COMPANY,
                                       as Escrow Agent



                                       By:_____________________________________

                                          Name:________________________________

                                          Title:_______________________________


Dated: _________, 199_


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1 To be deleted in the case of a Replacement Withdrawal scheduled for a date
which is not an Interest Payment Date (as defined in the Escrow and Paying Agent
Agreement).

2 To be inserted only in the case of a Replacement Withdrawal scheduled for a
date which is not an Interest Payment Date (as defined in the Escrow and Paying
Agent Agreement).