<PAGE>   1
                                                                     EXHIBIT 4.2






                                TRUST AGREEMENT

                                    Between

                ------------------------------------------------

                             AMERICA WEST AIRLINES

                                      And

                       FIDELITY MANAGEMENT TRUST COMPANY

                ------------------------------------------------

              FUTURE CARE - THE AMERICA WEST AIRLINES 401(K) PLAN

                                     TRUST








                         Dated as of December 31, 1993
<PAGE>   2
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
SECTION                                                                    PAGE
<S>                                                                        <C>
1 TRUST .................................................................    2

2 EXCLUSIVE BENEFIT AND REVERSION OF SPONSOR CONTRIBUTIONS ..............    2

3 DISBURSEMENT ..........................................................    2
  (a) Directions from Administrator
  (b) Limitations

4 INVESTMENT OF TRUST ...................................................    3
  (a) Selection of Investment Options
  (b) Available Investment Options
  (c) Participant Direction
  (d) Mutual Funds
  (e) Notes
  (f) Guaranteed Investment Contracts
  (g) Reliance of Trustee on Directions
  (h) Trustee Powers

5 RECORDKEEPING AND ADMINISTRATIVE SERVICES TO BE PERFORMED ..............   7
  (a) General
  (b) Accounts
  (c) Inspection and Audit
  (d) Effect of Plan Amendment
  (e) Returns, Reports and Information

6 COMPENSATION AND EXPENSES ..............................................   8

7 DIRECTIONS AND INDEMNIFICATION .........................................   9
  (a) Identity of Administrator and Named Fiduciary
  (b) Directions from Administrator
  (c) Directions from Named Fiduciary
  (d) Co-Fiduciary Liability
  (e) Indemnification
  (f) Survival

8 RESIGNATION OR REMOVAL OF TRUSTEE .....................................   10
  (a) Resignation
  (b) Removal
</TABLE>


                                      -i-



<PAGE>   3
                               TABLE OF CONTENTS
                                  (Continued)

<TABLE>
<CAPTION>
SECTION                                                                PAGE
-------                                                                ----
<S>      <C>                                                              <C>
 9       SUCCESSOR TRUSTEE............................................... 10
         (a) Appointment
         (b) Acceptance
         (c) Corporate Action

10       TERMINATION..................................................... 11

11       RESIGNATION, REMOVAL, AND TERMINATION NOTICES................... 11

12       DURATION........................................................ 11

13       AMENDMENT OR MODIFICATION....................................... 11

14       GENERAL......................................................... 11
         (a) Performance by Trustee, its Agent or Affiliates
         (b) Entire Agreement
         (c) Waiver
         (d) Successors and Assigns
         (e) Partial Invalidity
         (f) Section Headings

15       GOVERNING LAW................................................... 12
         (a) Massachusetts Controls
         (b) Trust Agreement Controls
</TABLE>

<TABLE>
<CAPTION>
SCHEDULES
---------
<S>       <C>
 A.       Recordkeeping and Administrative Services
 B.       Fee Schedule
 C.       Investment Options
 D.       Administrator's Authorization Letter
 E.       Named Fiduciary's Authorization Letter
 F.       IRS Determination Letter or Opinion of Counsel
 G.       Telephone Exchange Guidelines
</TABLE>

                                      -ii-
<PAGE>   4
     TRUST AGREEMENT, dated as of the 31st day of December, 1993, between
America West Airlines, an Arizona corporation, having an office at 4000 East Sky
Harbor Boulevard, Phoenix, AZ 85034 (the "Sponsor"), and FIDELITY MANAGEMENT
TRUST COMPANY, a Massachusetts trust company, having an office at 82 Devonshire
Street, Boston, Massachusetts 02109 (the "Trustee").

                                  WITNESSETH:

     WHEREAS, the Sponsor is the sponsor of Future Care - The America West
Airlines 401(k) Plan (the "Plan"); and

     WHEREAS, the Sponsor wishes to establish a trust to hold and invest assets
under the Plan for the exclusive benefit of participants in the Plan and their
beneficiaries; and

     WHEREAS, the Administration Committee (the "Named Fiduciary") is the named
fiduciary of the Plan (within the meaning of section 402(a) of the Employee
Retirement Income Security Act of 1974, as amended ("ERISA")); and

     WHEREAS, the Trustee is willing to hold and invest the aforesaid plan
assets in trust among several investment options selected by the Named
Fiduciary; and

     WHEREAS, the Sponsor wishes to have the Trustee perform certain ministerial
recordkeeping and administrative functions under the Plan; and

     WHEREAS, the Administrative Committee (the "Administrator") is the
administrator of the Plan (within the meaning of section 3(16)(A) of ERISA); and

     WHEREAS, the Trustee is willing to perform recordkeeping and administrative
services for the Plan if the services are purely ministerial in nature and are
provided within a framework of plan provisions, guidelines and interpretations
conveyed in writing to the Trustee by the Administrator.

     NOW, THEREFORE, in consideration of the foregoing premises and the mutual
covenants and agreements set forth below, the Sponsor and the Trustee agree as
follows:

                                       1
<PAGE>   5
SECTION 1.  TRUST. The Sponsor hereby establishes Future Care - The America West
Airlines 401(k) Plan Trust (the "Trust"), with the Trustee. The Trust shall
consist of an initial contribution of money or other property acceptable to the
Trustee in its sole discretion, made by the Sponsor or transferred from a
previous trustee under the Plan, such additional sums of money as shall from
time to time be delivered to the Trustee under the Plan, all investments made
therewith and proceeds thereof, and all earnings and profits thereon, less the
payments that are made by the Trustee as provided herein, without distinction
between principal and income. The Trustee hereby accepts the Trust on the terms
and conditions set forth in this Agreement. In accepting this Trust, the Trustee
shall be accountable for the assets received by it, subject to the terms and
conditions of this Agreement.

SECTION 2.  EXCLUSIVE BENEFIT AND REVERSION OF SPONSOR CONTRIBUTIONS. Except as
provided under applicable law, no part of the Trust may be used for, or diverted
to, purposes other than the exclusive benefit of the participants in the Plan or
their beneficiaries prior to the satisfaction of all liabilities with respect to
the participants and their beneficiaries.

SECTION 3.  DISBURSEMENTS.

         (a)  Directions from Administrator. The Trustee shall make
disbursements in the amounts and in the manner that the Administrator directs
from time to time in writing. The Sponsor hereby directs that, pursuant to the
Plan, a participant withdrawal request may be made by telephone and the Trustee
shall process such request only after the identity of the participant is
verified by use of a personal identification number ("PIN") and social security
number. The Trustee shall have no responsibility to ascertain any direction's
compliance with the terms of the Plan or of any applicable law or the
direction's effect for tax purposes or otherwise; nor shall the Trustee have any
responsibility to see to the application of any disbursement.

         (b)  Limitations. The Trustee shall not be required to make any
disbursement in excess of the net realizable value of the assets of the Trust at
the time of the disbursement. The Trustee shall not be required to make any
disbursement in cash unless the Administrator has provided a written direction
as to the assets to be converted to cash for the purpose of making the
disbursement.

                                       2
<PAGE>   6
SECTION 4. INVESTMENT OF TRUST

         (a)  Selection of Investment Options. The Trustee shall have no
responsibility for the selection of investment options under the Trust and shall
not render investment advice to any person in connection with the selection of
such options.

         (b)  Available Investment Options. The Named Fiduciary shall direct the
Trustee as to what investment options: (i) in which the Trust shall be invested
during the period beginning on the initial transfer of assets to the Trust and
ending on the completion of the reconciliation of participant records (the
"participant recordkeeping reconciliation period"), and (ii) the investment
options in which Plan participants may invest in, subject to the following
limitations. The Named Fiduciary may determine to offer as investment options
only (i) securities issued by the investment companies advised by Fidelity
Management & Research Company ("Mutual Funds"), (ii) a non-Fidelity Fund (with
mutual consent by written amendment to the Agreement), (iii) notes evidencing
loans to Plan participants in accordance with the terms of the Plan, (iv)
guaranteed investment contracts chosen by the Trustee, and (v) collective
investment funds maintained by the Trustee for qualified plans. The Trustee
shall be considered a fiduciary with investment discretion only with respect to
Plan assets that are invested in guaranteed investment contracts chosen by the
Trustee or in collective investment funds maintained by the Trustee for
qualified plans. The investment options initially selected by the Named
Fiduciary are identified on Schedules "A" and "C" attached hereto. The Named
Fiduciary may add additional investment options with the consent of the Trustee
and upon mutual amendment of this Trust Agreement and the Schedules thereto to
reflect such additions.

         (c)  Participant Direction. Each Plan participant shall direct the
Trustee in which investment option(s) to invest the assets in the participant's
individual accounts. Such directions may be made by Plan participants by use of
the telephone exchange system maintained for such purposes by the Trustee or its
agent, in accordance with written Telephone Exchange Guidelines attached hereto
as Schedule "G". In accordance with Section 404(c) of ERISA, a participant shall
be considered a named fiduciary of the Plan under ERISA for purposes of using
the telephone exchange system to provide investment directions to the Trustee
for the participant's individual account. In the event that the Trustee fails to
receive a proper direction, the assets shall be invested in the securities of
the Mutual Fund set forth for such purpose on Schedule "C", until the Trustee
receives a proper direction.

                                       3
<PAGE>   7
     (d) Mutual Funds. The Sponsor hereby acknowledges that it has received
from the Trustee a copy of the prospectus for each Mutual Fund selected by the
Named Fiduciary as a Plan investment option. Trust investments in Mutual Funds
shall be subject to the following limitations:

          (i) Execution of Purchases and Sales. Purchases and sales of Mutual
funds (other than for Exchanges) shall be made on the date on which the Trustee
receives from the Sponsor in good order all information and documentation
necessary to accurately effect such purchases and sales (or in the case of a
purchase, the subsequent date on which the Trustee has received a wire transfer
of funds necessary to make such purchase). Exchanges of Mutual Funds shall be
made in accordance with the Telephone Exchange Guidelines attached hereto as
Schedule "G".

          (ii) Voting. At the time of mailing of notice of each annual or
special stockholders' meeting of any Mutual Fund, the Trustee shall send a copy
of the notice and all proxy solicitation materials to each Plan participant who
has shares of the Mutual Fund credited to the participant's accounts, together
with a voting direction form for return to the Trustee or its designee. The
participant shall have the right to direct the Trustee as to the manner in which
the Trustee is to vote the shares credited to the participant's accounts (both
vested and unvested). The Trustee shall vote the shares as directed by the
participant. The Trustee shall not vote shares for which it has received no
directions from the participant. During the participant recordkeeping
reconciliation period, the Sponsor shall have the right to direct the Trustee as
to the manner in which the Trustee is to vote the shares of the Mutual Funds in
the Trust. With respect to all rights other than the right to vote, the Trustee
shall follow the directions of the participant and if no such directions are
received, the directions of the Named Fiduciary. The Trustee shall have no duty
to solicit directions from participants or the Sponsor.

     (e) Notes. The Administrator shall act as the Trustee's agent for the
purpose of holding all trust investments in participant loan notes and related
documentation and as such shall (i) hold physical custody of and keep safe the
notes and other loan documents, (ii) collect and remit all principal and
interest payments to the Trustee, (iii) keep the proceeds of such loans
separate from the other assets of the Administrator and clearly identify such
assets as Plan assets, and (iv) cancel and surrender the notes and other loan
documentation when a loan has been paid in full. To originate a participant
loan, the Plan participant shall direct the Trustee as to the type of loan to
be made from the participant's individual account. Such

                                       4
<PAGE>   8
directions shall be made by Plan participants by use of the telephone exchange
system maintained for such purpose by the Trustee or its agent. The Trustee
shall determine, based on the current value of the participant's account, the
amount available for the loan. Based on the quarterly interest rate supplied by
the Sponsor in accordance with the terms of the Plan, the Trustee shall advise
the participant of such interest rate, as well as the installment payment
amounts. The Trustee shall forward the loan document to the participant for
execution and submission for approval to the Administrator. The Administrator
shall have the responsibility for approving the loan and instructing the
Trustee to send the loan proceeds to the Administrator or to the participant if
so directed by the Administrator. In all cases, such instruction by the
Administrator shall be made within thirty (30) days of the participant's
initial request (the origination date).

     (f) Guaranteed Investment Contracts. Trust investments in guaranteed
investment contracts ("GICs") shall be subject to the following limitations:

          (i) Commingled Pool Investments. To the extent that the Named
Fiduciary selects as an investment option the Fidelity Managed Income Portfolio
of the Fidelity Group Trust for Employee Benefit Plans (the "Group Trust"), the
Sponsor hereby (A) agrees to the terms of the Group Trust and adopts said terms
as a part of this Agreement and (B) acknowledges that it has received from the
Trustee a copy of the Group Trust, the Declaration of Separate Fund for the
Fidelity Managed Income Portfolio of the Group Trust, and the Circular for the
Fidelity Managed Income Portfolio.

      (g) Reliance of Trustee on Directions.

          (i) The Trustee shall not be liable for any loss, or by reason of any
breach, which arises from any participant's exercise or non-exercise of rights
under this Section 4 over the assets in the participant's accounts.

          (ii) The Trustee shall not be liable for any loss, or by reason of
any breach, which arises from the Named Fiduciary's exercise or non-exercise of
rights under this Section 4, unless it was clear on their face that the actions
to be taken under the Named Fiduciary's directions were prohibited by the
fiduciary duty rules of section 404(a) of ERISA or were contrary to the terms
of the Plan or this Agreement.


                                       5
<PAGE>   9
     (h) Trustee Powers. The Trustee shall have the following powers and
authority;

          (i) Subject to paragraphs (b), (c) and (d) of this Section 4, to
sell, exchange, convey, transfer, or otherwise dispose of any property held in
the Trust, by private contract or at public auction. No person dealing with the
Trustee shall be bound to see to the application of the purchase money or other
property delivered to the Trustee or to inquire into the validity, expediency,
or propriety of any such sale or other disposition.

          (ii) Subject to paragraphs (b) and (c) of this Section 4, to invest
in guaranteed investment contracts and short term investments (including
interest bearing accounts with the Trustee or money market mutual funds advised
by affiliates of the Trustee) and in collective investment funds maintained by
the Trustee for qualified plans, in which case the provisions of each
collective investment fund in which the Trust is invested shall be deemed
adopted by the Sponsor and the provisions thereof incorporated as a part of
this Trust as long as the fund remains exempt from taxation under Sections
401(a) 501(a) of the Internal Revenue Code of 1986, as amended.

          (iii) To cause any securities or other property held as part of the
Trust to be registered in the Trustee's own name, in the name of one or more of
its nominees, or in the Trustee's account with the Depository Trust Company of
New York and to hold any investments in bearer form, but the books and records
of the Trustee shall at all times show that all such investments are part of
the Trust.

          (iv) To keep that portion of the Trust in cash or cash balances as
the Named Fiduciary or Administrator may, from time to time, deem to be in the
best interest of the Trust.

          (v) To make, execute, acknowledge, and deliver any and all documents
of transfer or conveyance and to carry out the powers herein granted.

          (vi) With prior written approval from the Sponsor, such approval not
to be unreasonably withheld, to settle, compromise, or submit to arbitration
any claims, debts, or damages due to or arising from the Trust; to commence or
defend suits or legal or administrative proceedings; to represent the Trust in
all suits and legal and administrative

                                       6
<PAGE>   10
hearings; and to pay all reasonable expenses arising from any such action, paid
by the Sponsor.

          (vii) With prior written approval from the Sponsor, such approval not
to be unreasonably withheld, to employ legal, accounting, clerical, and other
assistance as may be required in carrying out the provisions of this Agreement
and to pay their reasonable expenses and compensation from the Sponsor.

          (viii) To do all other acts although not specifically mentioned
herein, as the Trustee may deem necessary to carry out any of the foregoing
powers and the purposes of the Trust.

SECTION 5. RECORDKEEPING AND ADMINISTRATIVE SERVICES TO BE PERFORMED.

          (a) General. The Trustee shall perform those recordkeeping and
administrative functions described in Schedule "A" attached hereto. These
recordkeeping and administrative functions shall be performed within the
framework of the Administrator's written directions regarding the Plan's
provisions, guidelines and interpretations.

          (b) Accounts. The Trustee shall keep accurate accounts of all
investments, receipts, disbursements, and other transactions hereunder, and
shall report the value of the assets held in the Trust as of the last day of
each fiscal quarter of the Plan and the date on which the Trustee resigns or is
removed as provided in Section 8 of this Agreement or is terminated as provided
in Section 10 (the "Reporting Date"). Within thirty (30) days following each
Reporting Date or within sixty (60) days in the case of a Reporting Date caused
by the resignation or removal of the Trustee, or the termination of this
Agreement, the Trustee shall file with the Administrator a written account
setting forth all investments, receipts, disbursements, and other transactions
effected by the Trustee between the Reporting Date and the prior Reporting
Date, and setting forth the value of the Trust as of the Reporting Date. Except
as otherwise required under ERISA, upon the expiration of twelve (12) months
from the date of filing such account with the Administrator, the Trustee shall
have no liability or further accountability to anyone with respect to the
propriety of its acts or transactions shown in such account, except with
respect to such acts or transactions as to which the Sponsor shall within such
six (6) month period file with the Trustee written objections.

                                       7
<PAGE>   11
     (c)  Inspection and Audit.  All records generated by the Trustee in
accordance with paragraphs (a) and (b) shall be open to inspection and audit,
during the Trustee's regular business hours prior to the termination of this
Agreement, by the Administrator or any person designated by the Administrator.
Upon the resignation or removal of the Trustee or the termination of this
Agreement, the Trustee shall provide to the Administrator, at no expense to the
Sponsor, in the format regularly provided to the Administrator, a statement of
each participant's accounts as of the resignation, removal, or termination, and
the Trustee shall provide to the Administrator or the Plan's new recordkeeper
such further records as are reasonable, at the Sponsor's expense.

     (d)  Effect of Plan Amendment.  A confirmation of the current qualified
status of the Plan is attached hereto as Schedule "F". The Trustee's provision
of the recordkeeping and administrative services set forth in this Section 5
shall be conditioned on the Sponsor delivering to the Trustee a copy of any
amendment to the Plan as soon as administratively feasible following the
amendment's adoption, with, if requested, an IRS determination letter or an
opinion of counsel substantially in the form of Schedule "F" covering such
amendment, and on the Administrator providing the Trustee on a timely basis with
all the information the Administrator deems necessary for the Trustee to perform
the recordkeeping and administrative services and such other information as the
Trustee may reasonably request.

     (e)  Returns, Reports and Information.  The Administrator shall be
responsible for the preparation and timely filing of all returns, reports, and
information required of the Trust or Plan by law. The Trustee shall provide the
Administrator with such information as the Administrator may reasonably request
to make these filings. The Trustee will provide federal and/or state
truth-in-lending laws with regard to participant loans.

SECTION 6. COMPENSATION AND EXPENSES.  Within thirty (30) days of receipt of
the Trustee's bill, which shall be computed and billed in accordance with
Schedule "B" attached hereto and made a part hereof, as amended from time to
time, the Sponsor shall send to the Trustee a payment in such amount or the
Sponsor may direct the Trustee to deduct such amount from participants'
accounts. All expenses of the Trustee relating directly to the acquisition and
disposition of investments constituting part of the Trust, and all taxes of any
kind whatsoever that may be levied or assessed under existing or future laws
upon or in respect of the Trust or the income thereof, shall be a charge
against and paid from the appropriate Plan participants' accounts.


                                       8
<PAGE>   12
SECTION 7.  DIRECTIONS AND INDEMNIFICATION.

            (a)  Identity of Administrator and Named Fiduciary.  The Trustee
shall be fully protected in relying on the fact that the Named Fiduciary and
the Administrator under the Plan are the individuals or persons named as such
above or such other individuals or persons as the Sponsor may notify the
Trustee in writing.

            (b)  Directions from Administrator.  Whenever the Administrator
provides a direction to the Trustee, the Trustee shall not be liable for any
loss, or by reason of any breach, arising from the direction if the direction is
contained in a writing (or is oral and immediately confirmed in a writing)
signed by any individual whose name and signature have been submitted (and not
withdrawn) in writing to the Trustee by the Administrator in the form attached
hereto as Schedule "D", provided the Trustee reasonably believes the signature
of the individual to be genuine. Such direction may be made via EDT in
accordance with procedures agreed to by the Administrator and the Trustee;
provided, however, that the Trustee shall be fully protected in relying on such
direction as if it were a direction made in writing by the Administrator. The
Trustee shall have no responsibility to ascertain any direction's (i) accuracy,
(ii) compliance with the terms of the Plan or any applicable law, or (iii)
effect for tax purposes or otherwise.

            (c)  Directions from Named Fiduciary.  Whenever the Named Fiduciary
or Sponsor provides a direction to the Trustee, the Trustee shall not be liable
for any loss, or by reason of any breach, arising from the direction (i) if the
direction is contained in a writing (or is oral and immediately confirmed in a
writing) signed by any individual whose name and signature have been submitted
(and not withdrawn) in writing to the Trustee by the Named Fiduciary in the
form attached hereto as Schedule "E" and (ii) if the Trustee reasonably
believes the signature of the individual to be genuine, unless it is clear on
the direction's face that the actions to be taken under the direction would be
prohibited by the fiduciary duty rules of section 404(a) of ERISA or would be
contrary to the terms of the Plan or this Agreement.

            (d)  Co-Fiduciary Liability.  In any other case, the Trustee shall
not be liable for any loss, or by reason of any breach, arising from any act or
omission of another fiduciary under the Plan except as provided in section
405(a) of ERISA.

            (e)  Indemnification.  The Sponsor shall indemnify the Trustee
against, and hold the Trustee harmless from, any and all loss, damage, penalty,
liability, cost, and expense,


                                       9

<PAGE>   13
including without limitation, reasonable attorneys' fees and disbursements,
that may be incurred by, imposed upon, or asserted against the Trustee by
reason of any claim, regulatory proceeding, or litigation arising from any act
done or omitted to be done by any individual or person with respect to the Plan
or Trust, excepting only any and all loss, etc., arising solely from the
Trustee's negligence, bad faith, errors or breaches of this Agreement, as
required under ERISA.

          (f) Survival.  The provisions of this Section 7 shall survive the
termination of this Agreement.

SECTION 8.  RESIGNATION OR REMOVAL OF TRUSTEE.

          (a) Resignation.  The Trustee may resign at any time upon ninety (90)
days' notice in writing to the Sponsor, unless a shorter period of notice is
agreed upon by the Sponsor.

          (b) Removal.  The Sponsor may remove the Trustee at any time upon
thirty (30) days' notice in writing to the Trustee, unless a shorter period of
notice is agreed upon by the Trustee.

SECTION 9. SUCCESSOR TRUSTEE.

          (a) Appointment.  If the office of Trustee becomes vacant for any
reason, the Sponsor may in writing appoint a successor trustee under this
Agreement. The successor trustee shall have all of the rights, powers,
privileges, obligations, duties, liabilities, and immunities granted to the
Trustee under this Agreement. The successor trustee and predecessor trustee
shall not be liable for the acts or omissions of the other with respect to the
Trust.

          (b)  Acceptance.  When the successor trustee accepts its appointment
under this Agreement, title to and possession of the Trust assets shall
immediately vest in the successor trustee without any further action on the
part of the predecessor trustee. The predecessor trustee shall execute all
instruments and do all acts that reasonably may be necessary or reasonably may
be requested in writing by the Sponsor or the successor trustee to vest title
to all Trust assets in the successor trustee or to deliver all Trust assets to
the successor trustee.

                                       10
<PAGE>   14
     (c)  Corporate Action.  Any successor of the Trustee or successor trustee,
through sale or transfer of the business or trust department of the Trustee or
successor trustee, or through reorganization, consolidation, or merger, or any
similar transaction, shall, upon consummation of the transaction, become the
successor trustee under this Agreement.

SECTION 10.  TERMINATION.  This Agreement may be terminated at any time by the
Sponsor upon thirty (30) days' notice in writing to the Trustee. On the date of
the termination of this Agreement, the Trustee shall forthwith transfer and
deliver to such individual or entity as the Sponsor shall designate, all cash
and assets then constituting the Trust. If, by the termination date, the
Sponsor has not notified the Trustee in writing as to whom the assets and cash
are to be transferred and delivered, the Trustee may bring an appropriate
action or proceeding for leave to deposit the assets and cash in a court of
competent jurisdiction. The Trustee shall be reimbursed by the Sponsor for all
costs and expenses of the action or proceeding including, without limitation,
reasonable attorneys' fees and disbursements.

SECTION 11.  RESIGNATION, REMOVAL, AND TERMINATION NOTICES.  All notices of
resignation, removal or termination under this Agreement must be in writing and
mailed to the party to which the notice is being given by certified or
registered mail, return receipt requested, to the Sponsor c/o Jill O'Sullivan,
America West Airlines, 4000 East Sky Harbor Blvd., Phoenix, AZ, 85034 and to
the Trustee c/o John M. Kimpel, Fidelity Investments, 82 Devonshire Street,
Boston, Massachusetts 02109, or to such other addresses as the parties have
notified each other of in the foregoing matter.

SECTION 12.  DURATION.  The Trust shall continue in effect without limit as to
time, subject, however, to the provisions of this Agreement relating to
amendment, modification, and termination thereof.

SECTION 13.  AMENDMENT OR MODIFICATION.  This Agreement may be amended or
modified at any time and from time to time only by an instrument executed by
both the Sponsor and the Trustee. Notwithstanding the foregoing, to reflect
increased operating costs the Trustee may once each calendar year (beginning
December 31, 1995) amend Schedule "B" without the Sponsor's consent upon
seventy-five (75) days' written notice to the Sponsor.

                                       11
<PAGE>   15
SECTION 14. GENERAL.

     (a)  Performance by Trustee, its Agents or Affiliates. The Sponsor
acknowledges and authorizes that the services to be provided under this
Agreement shall be provided by the Trustee, its agents or affiliates, including
Fidelity Investments Institutional Operations Company or its successor, and that
certain of such services may be provided pursuant to one or more other
contractual agreements or relationships. Whenever the Trustee uses an affiliate,
the Trustee shall be fully responsible for all of the actions of that
affiliate.

     (b)  Entire Agreement. This Agreement contains all of the terms agreed
upon between the parties with respect to the subject matter hereof.

     (c)  Waiver. No waiver by either party of any failure or refusal to comply
with an obligation hereunder shall be deemed a waiver of any other or
subsequent failure or refusal to so comply.

     (d)  Successors and Assigns. All rights and duties in this Agreement shall
inure to the benefit of, and shall bind, the successors and assigns of the
respective parties.

     (e)  Partial Invalidity. If any term or provision of this Agreement or the
application thereof to any person or circumstances shall, to any extent, be
invalid or unenforceable, the remainder of this Agreement, or the application
of such term or provision to person or circumstances other than those as to
which it is held invalid or unenforceable, shall not be affected thereby, and
each term and provision of this Agreement shall be valid and enforceable to the
fullest extent permitted by law.

     (f)  Section Headings. The headings of the various sections and
subsections of this Agreement have been inserted only for the purposes of
convenience and are not part of this Agreement and shall not be deemed in any
manner to modify, explain, expand or restrict any of the provisions of this
Agreement.

                                       12


<PAGE>   16
SECTION 15. GOVERNING LAW.

     (a)  Massachusetts Law Controls.  This Agreement is being made in the
Commonwealth of Massachusetts, and the Trust shall be administered as a
Massachusetts trust. The validity, construction, effect, and administration of
this Agreement shall be governed by and interpreted in accordance with the laws
of the Commonwealth of Massachusetts, except to the extent those laws are
superseded under section 514 of ERISA.

     (b)  Trust Agreement Controls.  The Trustee is not a party to the Plan,
and in the event of any conflict between the provisions of the Plan and the
provisions of this Agreement, the provisions of this Agreement shall control.

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

                                       AMERICA WEST AIRLINES
                                       ADMINISTRATIVE COMMITTEE




Attest: /s/ M. J Whalen              By: /s/ A. E. Frei
        -------------------------        ----------------------------
        Secretary                        Vice President

                                         FIDELITY MANAGEMENT TRUST
                                         COMPANY



Attest: /s/ Douglas O. Kent          BY  /s/ John P. O'Reilly, Jr.
        ------------------------         ----------------------------
        Assistant Clerk                  Senior Vice President






                                      13

<PAGE>   17
                                  SCHEDULE "A"

                   RECORDKEEPING AND ADMINISTRATIVE SERVICES

Administration
--------------

* Establishment and maintenance of participant account and election percentages.

* Maintenance of seven (7) plan investment options:

  - Fidelity Puritan Fund
  - Fidelity Magellan Fund
  - Fidelity Managed Income Portfolio
  - Fidelity Asset Manager: Income
  - Fidelity Asset Manager
  - Fidelity Asset Manager: Growth
  - Fidelity Growth Company Fund

* Maintenance of six (6) money classifications:

  - Basic Employee Pre-Tax
  - Company Match
  - Discretionary Cont.
  - QNEC
  - Rollover
  - Supplemental Employee Pre-Tax

* Processing of mutual fund trades.

  The Trustee will provide only the recordkeeping and administrative services
  set forth on this Schedule "A" and no others.

Processing
----------

* Processing of contribution data three times per month.
* Daily processing of transfers and changes of future allocations and deferral
  percentages.
* Semi-Monthly processing of withdrawals.

Other
-----

* Monthly trial balance
* Quarterly administrative reports
* Quarterly participant statements
* 1099-Rs
* Participant Loans
* Performance of section 401(k) limitation testing upon request. In order to
  obtain this service, the client shall be required to provide the information
  identified in the Fidelity Discrimination Testing Package Guidelines.

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<PAGE>   18
-    Employee communications describing available investment options, including
     multimedia informational materials and group presentations.

-    Daily processing of in-service and hardship withdrawals via telephone as
     approved and directed by the Sponsor

-    Enrollments by telephone at no charge.

-    Maintain HCE record on FPRS

-    Maintain IRS limits on FPRS (i.e. 401(g) and 401(k) maximums)

AMERICA WEST AIRLINES                        FIDELITY MANAGEMENT TRUST
ADMINISTRATIVE COMMITTEE                     COMPANY


By: /s/ Jim O'Sullivan      12/27/93     By:  /s/ John P. O'Reilly, Jr.  1/10/94
   ---------------------------------          ----------------------------------
                               Date           Senior Vice President       Date


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