Document:

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                                                                     EXHIBIT 4.5

                          TRUST SUPPLEMENT No. 2000-3C
                          Dated as of November 2, 2000

                                     between

               STATE STREET BANK AND TRUST COMPANY OF CONNECTICUT,
                              NATIONAL ASSOCIATION
                                   as Trustee,

                                       and

                                US AIRWAYS, INC.

                                       to

                          PASS THROUGH TRUST AGREEMENT
                           Dated as of October 5, 2000

                      US Airways Pass Through Trust 2000-3C
                                8.39% US Airways
                           Pass Through Certificates,
                                 Series 2000-3C

            This Trust Supplement No. 2000-3C, dated as of November 2, 2000
(herein called the "Trust Supplement"), between US Airways, Inc., a Delaware
corporation (the "Company") and State Street Bank and Trust Company of
Connecticut, National Association (the "Trustee"), to the Pass Through Trust
Agreement, dated as of October 5, 2000, between the Company and the Trustee (the
"Basic Agreement").

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                                   WITNESSETH:

            WHEREAS, the Basic Agreement, unlimited as to the aggregate
principal amount of Certificates (unless otherwise specified herein, capitalized
terms used herein without definition having the respective meanings specified in
the Basic Agreement) which may be issued thereunder, has heretofore been
executed and delivered;

            WHEREAS, the Company obtained commitments from AVSA for the delivery
of twenty-three (23) Aircraft;

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

            WHEREAS, in the case of each Leased Aircraft, each Owner Trustee,
acting on behalf of the corresponding Owner Participant, will issue pursuant to
an Indenture, on a non-recourse basis, Equipment Notes in order to finance a
portion of its purchase price of such Leased Aircraft;

            WHEREAS, in the case of each Owned Aircraft, the Company will issue
pursuant to an Indenture, on a recourse basis, Equipment Notes to finance a
portion of the purchase price of such Owned Aircraft;

            WHEREAS, the Trustee hereby declares the creation of this US Airways
Pass Through Trust 2000-3C (the "Applicable Trust") for the benefit of the
Applicable Certificateholders, and the initial Applicable Certificateholders as
the grantors of the Applicable Trust, by their respective acceptances of the
Applicable Certificates, join in the creation of the Applicable Trust with the
Trustee;

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

            WHEREAS, the Escrow Agent, the Trustee, the Escrow Paying Agent, and
AIFS have contemporaneously herewith entered into an Escrow Agreement with the
Escrow Paying Agent pursuant to which AIFS has delivered to the Escrow Agent the
proceeds from the sale of the Applicable Certificates and has irrevocably
instructed the Escrow Agent to withdraw and pay funds from such proceeds upon
request and proper certification by the Trustee to purchase Equipment Notes as
the Aircraft are delivered by AVSA under the Aircraft Purchase Agreement from
time to time prior to the Delivery Period Termination Date;

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

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            WHEREAS, pursuant to the terms and conditions of the Basic Agreement
as supplemented by this Trust Supplement (the "Agreement") and the Note Purchase
Agreement, the Trustee on behalf of the Applicable Trust, using funds withdrawn
under the Escrow Agreement, shall purchase one or more Equipment Notes having
the same interest rate as, and Final Legal Distribution Date not later than the
final Regular Distribution Date of, the Applicable Certificates issued hereunder
and, in each case, shall hold such Equipment Notes in trust for the benefit of
the Applicable Certificateholders; and

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

            NOW THEREFORE, in consideration of the premises herein, it is agreed
between the Company and the Trustee as follows:

                                    ARTICLE I
                                THE CERTIFICATES

            Section 1.01. The Certificates. There is hereby created a series of
certificates to be issued under the Agreement to be distinguished and known as
"8.39% US Airways Pass Through Certificates, Series 2000-3C" (including any
Exchange Certificates and any Private Exchange Certificates) (hereinafter
defined as the "Applicable Certificates"). Each Applicable Certificate
represents a fractional undivided interest in the Applicable Trust created
hereby. The Applicable Certificates shall be the only instruments evidencing a
fractional undivided interest in the Applicable Trust.

            The terms and conditions applicable to the Applicable Certificates
are as follows:

            (a) The aggregate principal amount of the Applicable Certificates
      that shall be authenticated under the Agreement (except for Applicable
      Certificates authenticated and delivered pursuant to Sections 3.03, 3.04
      and 3.06 of the Basic Agreement and in connection with the Registration
      Agreement) is $157,054,000.

            (b) The Regular Distribution Dates with respect to any payment of
      Scheduled Payments means March 1 and September 1 of each year, commencing
      on March 1, 2001, until payment of all of the Scheduled Payments to be
      made under the Equipment Notes has been made.

            (c) The Special Distribution Dates with respect to the Applicable
      Certificates means any Business Day on which a Special Payment is to be
      distributed pursuant to the Agreement.

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            (d) At the Escrow Agent's request under the Escrow Agreement, the
      Trustee shall affix the corresponding Escrow Receipt to each Applicable
      Certificate. In any event, any transfer or exchange of any Applicable
      Certificate shall also effect a transfer or exchange of the related Escrow
      Receipt. Prior to the Final Withdrawal Date, no transfer or exchange of
      any Applicable Certificate shall be permitted unless the corresponding
      Escrow Receipt is attached thereto and also is so transferred or
      exchanged. By acceptance of any Applicable Certificate to which an Escrow
      Receipt is attached, each Holder of such an Applicable Certificate
      acknowledges and accepts the restrictions on transfer of the Escrow
      Receipt set forth herein and in the Escrow Agreement.

            (e) (i) The Applicable Certificates shall be in the form attached
      hereto as Exhibit A. Any Person acquiring or accepting an Applicable
      Certificate or an interest therein will, by such acquisition or
      acceptance, be deemed to represent and warrant that either (i) the assets
      of an employee benefit plan subject to Title I of the Employee Retirement
      Income Security Act of 1974, as amended ("ERISA"), or of a plan subject to
      Section 4975 of the Internal Revenue Code of 1986, as amended (the
      "Code"), have not been used to purchase Applicable Certificates or an
      interest therein or (ii) the purchase and holding of Applicable
      Certificates is exempt from the prohibited transaction restrictions of
      ERISA and the Code pursuant to one or more prohibited transaction
      statutory or administrative exemptions.

            (ii) The Applicable Certificates shall be Book-Entry Certificates
      and shall be subject to the conditions set forth in the Letter of
      Representations between the Company and the Clearing Agency attached
      hereto as Exhibit E.

            (f) The Applicable Certificates are subject to the Intercreditor
      Agreement, the Deposit Agreement and the Escrow Agreement.

            (g) The Applicable Certificates will have the benefit of the
      Liquidity Facility and the Registration Agreement.

            (h) The Responsible Party is the Company.

            (i) The particular "sections of the Note Purchase Agreement", for
      purposes of clause (3) of Section 7.07 of the Basic Agreement, are Section
      6(b) (with respect to Owned Aircraft) and Section 6(c) (with respect to
      Leased Aircraft) of the relevant Participation Agreement attached as an
      exhibit to the Note Purchase Agreement.

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                                   ARTICLE II
                                   DEFINITIONS

            Section 2.01. Definitions. Capitalized terms used but not otherwise
defined herein shall have the meaning ascribed to them in the Basic Agreement.
For all purposes of the Basic Agreement as supplemented by this Trust
Supplement, the following capitalized terms have the following meanings:

            Agreement: Has the meaning specified in the recitals hereto.

            AIFS: Means Airbus Industrie Financial Services.

            Aircraft: Means each of the New Aircraft or Substitute Aircraft in
      respect of which a Participation Agreement is entered into in accordance
      with the Note Purchase Agreement.

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

            Applicable Certificate: Has the meaning specified in Section 1.01 of
      this Agreement.

            Applicable Certificateholder: Means the Person in whose name an
      Applicable Certificate is registered on the Register for the Applicable
      Certificates.

            Applicable Delivery Date: Has the meaning specified in Section
      5.01(b) of this Trust Supplement.

            Applicable Participation Agreement: Has the meaning specified in
      Section 5.01(b) of this Trust Supplement.

            AVSA: Means AVSA, S.A.R.L.

            Business Day: Means any day other than a Saturday, a Sunday or other
      day on which insurance companies or commercial banks in New York, New York
      or commercial banking institutions in Pittsburgh, Pennsylvania and in the
      cities in which the Corporate Trust Office of the Subordination Agent or
      any Loan Trustee or the fiscal agent of the Policy Provider or the office
      of the Policy Prover are located are authorized or obligated by law or
      executive order to close.

            Class C Purchase Agreement: Means the Purchase Agreement dated as of
      October 26, 2000 between AIFS and the Company, as the same may be amended,
      supplemented or otherwise modified from time to time in accordance with
      its terms.

            Class G Agreement: Means the Basic Agreement as supplemented by the
      Trust Supplement No. 2000-3G.

            Class G Certificates: Means the 7.89% US Airways Pass Through
      Certificates, Series 2000-3G.

            Class G Certificateholder: Means a holder of Class G Certificates.

            Class G Trustee: Means the Trustee under the Class G Agreement.

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            Closing Notice: Means the Closing Notice as defined in and delivered
      pursuant to Section 2(b) of the Note Purchase Agreement.

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

            Delivery Date: Has the meaning specified in the Participation
      Agreements.

            Delivery Notice: Has the meaning specified in the Participation
      Agreements.

            Delivery Period Termination Date: Means the earlier of (a) July 1,
      2001 and (b) the date on which Equipment Notes issued with respect to all
      of the New Aircraft (or Substitute Aircraft in lieu thereof) have been
      purchased by the Applicable Trust and the Class G Trust in accordance with
      the Note Purchase Agreement.

            Deposits: Has the meaning specified in the Deposit Agreement.

            Deposit Agreement: Means the Deposit Agreement dated as of November
      2, 2000 relating to the Applicable Certificates between the Depositary and
      the Escrow Agent, as the same may be amended, supplemented or otherwise
      modified from time to time in accordance with its terms.

            Depositary: Means ABN AMRO Bank N.V., acting through its Chicago
      branch, and any replacement or successor therefor.

            Distribution Date: Means any Regular Distribution Date or Special
      Distribution Date as the context requires.

            Escrow Agent: Means, initially, First Security Bank, National
      Association, and any replacement or successor therefor appointed in
      accordance with the Escrow Agreement.

            Escrow Agreement: Means the Escrow and Paying Agent Agreement dated
      as of November 2, 2000 relating to the Applicable Certificates, among the
      Escrow Agent, the Escrow Paying Agent, the Trustee and AIFS, as the same
      may be amended, supplemented or otherwise modified from time to time in
      accordance with its terms.

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

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

            Exchange Certificate: Means any of the certificates, substantially
      in the form of Exhibit A, issued in exchange for an Initial Certificate
      pursuant to the Registration Agreement and authenticated under this
      Agreement.

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            Exchange Offer Registration Statement: Means the Exchange Offer
      Registration Statement defined in the Registration Agreement.

            Final Legal Distribution Date: Means, with respect to the Applicable
      Certificates, September 1, 2023.

            Final Withdrawal: Has the meaning specified in Section 1.2 of the
      Escrow Agreement.

            Final Withdrawal Date: Has the meaning specified in Section 1.2 of
      the Escrow Agreement.

            Final Withdrawal Notice: Has the meaning specified in Section 5.02
      of this Trust Supplement.

            Global Certificates: Has the meaning assigned to such term in
      Section 9.01(a).

            Indenture: Means each of the separate trust indentures and mortgages
      relating to the Aircraft, in each case as the same may be amended,
      supplemented or otherwise modified from time to time in accordance with
      its terms.

            Initial Certificate: Means any of the certificates issued and
      authenticated, under this Agreement, substantially in the form of Exhibit
      A, other than an Exchange Certificate or a Private Exchange Certificate.

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

            Intercreditor Agreement: Means the Intercreditor Agreement dated as
      of November 2, 2000 among the Trustee, the Class G Trustee, the Liquidity
      Provider, the Policy Provider, and State Street Bank and Trust Company of
      Connecticut, National Association, as Subordination Agent and as trustee
      thereunder, as amended, supplemented or otherwise modified from time to
      time in accordance with its terms.

            Investors: Means AIFS together with all subsequent beneficial owners
      of the Applicable Certificates.

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

            Leased Aircraft: Has the meaning specified in the third recital to
      this Trust Supplement.

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            Liquidity Facility: Means, initially, the Revolving Credit Agreement
      dated as of November 2, 2000 relating to the Applicable Certificates,
      between the Liquidity Provider and State Street Bank and Trust Company of
      Connecticut, National Association, as Subordination Agent, as agent and
      trustee for the Applicable Trust, and, from and after the replacement of
      such agreement pursuant to the Intercreditor Agreement, the replacement
      liquidity facility therefor, in each case as amended, supplemented or
      otherwise modified from time to time in accordance with their respective
      terms.

            Liquidity Provider: Means, initially, Morgan Stanley Capital
      Services Inc., and any replacements or successors therefor appointed in
      accordance with the Intercreditor Agreement.

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

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

            Note Documents: Means the Note Purchase Agreement, this Trust
      Supplement and, with respect to any Equipment Note, means (i) the
      Indenture and the Participation Agreement relating to such Equipment Note,
      and (ii) in the case of any Equipment Note related to a Leased Aircraft,
      the Lease relating to such Leased Aircraft.

            Note Purchase Agreement: Means the Note Purchase Agreement dated as
      of November 2, 2000 among the Trustee, the Class G Trustee, the Company,
      the Escrow Agent, the Escrow Paying Agent and the Subordination Agent,
      providing for, among other things, the purchase of certain Equipment Notes
      by the Trustee on behalf of the Trust, as the same may be amended,
      supplemented or otherwise modified from time to time, in accordance with
      its terms.

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

            Offering Memorandum: Means the Confidential Offering Memorandum,
      dated November 2, 2000, relating to the offering of the Applicable
      Certificates.

            Owned Aircraft: Has the meaning specified in the third recital to
      this Trust Supplement.

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

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

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

            Physical Certificates: Has the meaning specified in Section
      10.01(b).

            Policy: Has the meaning specified in the Intercreditor Agreement.

            Policy Provider: Has the meaning specified in the Intercreditor
      Agreement.

            Policy Provider Default: Has the meaning specified in the
      Intercreditor Agreement.

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

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

            Private Exchange Certificate: Means any of the certificates,
      substantially in the form of Exhibit A, issued in exchange for an Initial
      Certificate pursuant to the Registration Agreement and authenticated under
      this Agreement.

            Private Placement Legend: Has the meaning specified in Section
      10.02(a).

            Prospectus Supplement: Means the Prospectus Supplement dated October
      26, 2000, relating to the offering of the Class G Certificates.

            PTC Event of Default: Means, with respect to the Applicable
      Certificates, any failure to pay within ten Business Days of the due date
      thereof: (i) the outstanding Pool Balance of the Applicable Certificates
      on the Final Legal Distribution Date for the Applicable Certificates or
      (ii) interest due on the Applicable Certificates on any Distribution Date
      (unless the Subordination Agent shall have made an Interest Drawing, or a
      withdrawal from the Cash Collateral Account or a drawing under the Policy
      with respect thereto in an aggregate amount sufficient to pay such
      interest and shall have distributed such amount to the Trustee).

<PAGE>

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

            Registration Agreement: Means the Registration Agreement, dated as
      of the date hereof, between the Initial Purchaser, the Trustee and the
      Company, as amended, supplemented or otherwise modified from time to time
      in accordance with its terms.

            Registration Statement: Means the Registration Statement defined in
      the Registration Agreement.

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

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

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

            Scheduled Payment: Means, with respect to any Equipment Note, (i)
      any payment of principal or interest on such Equipment Note (other than
      any such payment which is not in fact received by the Trustee or any
      Subordination Agent within five days of the date on which such payment is
      scheduled to be made) or (ii) any payment of interest on the Applicable
      Certificates with funds drawn under the Liquidity Facility (other than any
      such payment which is not in fact received by the Trustee or any
      Subordination Agent within five days of the date upon which payment is
      scheduled to be made), which payment in the case of clauses (i) or (ii)
      represents the installment of principal on such Equipment Note at the
      stated maturity of such installment, the payment of regularly scheduled
      interest accrued on the unpaid principal amount of such Equipment Note, or
      both; provided, however, that any payment of principal, premium, if any,
      or interest resulting from the redemption or purchase of any Equipment
      Note shall not constitute a Scheduled Payment.

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

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

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

            Termination Date: Means the date on which first occurs a
      "Termination Event" as defined in that certain Aircraft Financing Letter
      Agreement, dated as of October 31, 1997 between AVSA, S.A.R.L. and the
      Company.

<PAGE>

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

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

                                   ARTICLE III
                 DISTRIBUTIONS; STATEMENTS TO CERTIFICATEHOLDERS

            Section 3.01. Additions to Article IV of the Basic Agreement. In
addition to the provisions of Article IV of the Basic Agreement, the following
provisions shall apply to the Applicable Trust:

            (a) Upon the payment of Special Redemption Premium to the Trustee
      under the Note Purchase Agreement, the Trustee, upon receipt thereof,
      shall immediately deposit the aggregate amount of such Special Redemption
      Premium in the Special Payments Account;

            (b) The distribution of amounts of Special Redemption Premium as
      provided for in Section 4.02(b) of the Basic Agreement shall be on the
      Special Distribution Date with respect to such Special Payment or as soon
      thereafter as the Trustee has confirmed receipt of the related Special
      Redemption Premium;

            (c) In the event of the payment of a Special Redemption Premium by
      the Company to the Trustee under the Note Purchase Agreement, the notice
      provided for in Section 4.02(c) of the Basic Agreement shall be mailed,
      together with the notice by the Escrow Paying Agent under Section 2.06 of
      the Escrow Agreement, not less than 15 days prior to the Special
      Distribution Date for such amount, which Special Distribution Date shall
      be the Final Withdrawal Date; and

            (d) The last sentence of the first paragraph of Section 4.02(c) of
      the Basic Agreement shall apply equally if the amount of Special
      Redemption Premium, if any, has not been calculated at the time the
      Trustee mails notice of a Special Payment.

<PAGE>

            Section 3.02. Statements to Applicable Certificateholders. (a) On
each Distribution Date, the Trustee will include with each distribution to
Applicable Certificateholders of a Scheduled Payment or Special Payment, as the
case may be, a statement setting forth the information provided below (in the
case of a Special Payment, including any Special Redemption Premium, reflecting
in part the information provided by the Escrow Paying Agent under the Escrow
Agreement). Such statement shall set forth (per $1,000 face amount Applicable
Certificate as to (ii), (iii), (iv) and (v) below) the following information:

            (i) the aggregate amount of funds distributed on such Distribution
      Date under the Agreement and under the Escrow Agreement, indicating the
      amount allocable to each source including any portion thereof paid by the
      Liquidity Provider;

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

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

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

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

            (vi) the Pool Balance and the Pool Factor.

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

            (b) Within a reasonable period of time after the end of each
calendar year but not later than the latest date permitted by law, the Trustee
shall furnish to each Person who at any time during such calendar year was an
Applicable Certificateholder of record a statement containing the sum of the
amounts determined pursuant to clauses (a)(i), (a)(ii), (a)(iii), (a)(iv) and
(a)(v) of this Section 3.02 for such calendar year or, in the event such Person
was an Applicable Certificateholder of record during a portion of such calendar
year, for such portion of such year, and such other items as are readily
available to the Trustee and which an Applicable Certificateholder shall
reasonably request as necessary for the purpose of such Applicable
Certificateholder's preparation of its federal income tax returns. Such
statement and such other items shall be prepared on the basis of information
supplied to the Trustee by the Clearing Agency Participants and shall be
delivered by the Trustee to such Clearing Agency Participants to be available
for forwarding by such Clearing Agency Participants to the holders of interests
in the Applicable Certificates in the manner described in Section 3.02(a) of
this Trust Supplement.

<PAGE>

            (c) Promptly following (i) the Cut-Off Date, if there has been any
change in the information set forth in clauses (x), (y) and (z) below from that
set forth in page S-45 of the Prospectus Supplement, and (ii) any early
redemption or purchase of, or any default in the payment of principal or
interest in respect of, any of the Equipment Notes held in the Applicable Trust,
or any Final Withdrawal, the Trustee shall furnish to Applicable
Certificateholders of record on such date a statement setting forth (x) the
expected Pool Balances for each subsequent Regular Distribution Date following
the Cut-Off Date, (y) the related Pool Factors for such Regular Distribution
Dates and (z) the expected principal distribution schedule of the Equipment
Notes, in the aggregate, held as Trust Property at the date of such notice. With
respect to the Applicable Certificates registered in the name of a Clearing
Agency, on the Cut-Off Date, the Trustee will request from such Clearing Agency
a securities position listing setting forth the names of all Clearing Agency
Participants reflected on such Clearing Agency's books as holding interests in
the Applicable Certificates on such date. The Trustee will mail to each such
Clearing Agency Participant the statement described above and will make
available additional copies as requested by such Clearing Agency Participant for
forwarding to holders of interests in the Applicable Certificates.

            (d) This Section 3.02 supersedes and replaces Section 4.03 of the
      Basic Agreement.

                                   ARTICLE IV
                                     DEFAULT

            Section 4.01. Purchase Rights of Certificateholders. (a) (i) At any
time after the occurrence and during the continuance of a Triggering Event, each
Applicable Certificateholder shall have the right to purchase, for the purchase
price set forth below, all, but not less than all, of the Class G Certificates
upon ten days' written notice to the Trustee, and each other Applicable
Certificateholder, provided that (A) if prior to the end of such ten-day period
any other Applicable Certificateholder notifies such purchasing Applicable
Certificateholder that such other Applicable Certificateholder wants to
participate in such purchase, then such other Applicable Certificateholder may
join with the purchasing Applicable Certificateholder to purchase all, but not
less than all, of the Class G Certificates pro rata based on the Fractional
Undivided Interest in the Applicable Trust held by each such Applicable
Certificateholder and (B) if prior to the end of such ten-day period any other
Applicable Certificateholder fails to notify the purchasing Applicable
Certificateholder of such other Applicable Certificateholder's desire to
participate in such a purchase, then such other Applicable Certificateholder
shall lose its right to purchase the Class G Certificates pursuant to this
Section 4.01(a) and (ii) whether or not any Applicable Certificateholder
exercises its right to purchase pursuant to clause (a)(i) above, the Policy
Provider, if it is then the Controlling Party and 180 days have elapsed since
the occurrence of a Triggering Event that is continuing, shall have the right
(except in the event of a Policy Provider Default) to purchase all, but not less
than all, of the Class G Certificates upon ten days' written notice to the
Trustee, the trustee of the Class G Trust and the Class G Certificateholders.

<PAGE>

            The purchase price with respect to the Class G Certificates shall be
equal to the Pool Balance of the Class G Certificates, together with accrued and
unpaid interest thereon to the date of such purchase, without premium, but
including any other amounts then due and payable to the Class G
Certificateholders under this Agreement, the Intercreditor Agreement, the Escrow
Agreement or any Note Document or on or in respect of the Applicable
Certificates; provided, however, that (x) if such purchase occurs after the
record date specified in Section 2.03(b) of the Escrow Agreement relating to the
distribution of unused Deposits and accrued and unpaid interest thereunder, such
purchase price shall be reduced by the aggregate amount of unused Deposits and
interest to be distributed under the Escrow Agreement (which deducted amounts
shall remain distributable to, and may be retained by, the Class G
Certificateholder as of such Record Date) and (y) if such purchase occurs after
a Record Date, such purchase price shall be reduced by the amount to be
distributed hereunder on the related Distribution Date (which deducted amounts
shall remain distributable to, and may be retained by, the Class G
Certificateholder as of such Record Date); provided further that no such
purchase of Class G Certificates shall be effective unless the purchaser(s)
shall certify to the Trustee that contemporaneously with such purchase, such
purchaser(s) is purchasing the Class G Certificates pursuant to the terms of
this Agreement. Each payment of the purchase price of the Class G Certificates
referred to in the first sentence hereof shall be made to an account or accounts
designated by the Trustee and each such purchase shall be subject to the terms
of this Section 4.01(a).

            (b) This Section 4.01 supersedes and replaces Section 6.01(b) of the
      Basic Agreement.

                                    ARTICLE V
                                   THE TRUSTEE

            Section 5.01. Delivery of Documents; Delivery Dates. (a) The Trustee
is hereby directed (i) to execute and deliver the Intercreditor Agreement, the
Escrow Agreement, the Registration Agreement and the Note Purchase Agreement,
each in the form delivered to the Trustee by the Company and (ii) subject to the
respective terms thereof, to perform its obligations thereunder. Upon request of
the Company and the satisfaction or waiver of the closing conditions specified
in the Class C Purchase Agreement, the Trustee shall execute, deliver,
authenticate, issue and sell Applicable Certificates in authorized denominations
equaling in the aggregate the amount set forth, with respect to the Applicable
Trust, in Schedule I to the Class C Purchase Agreement evidencing the entire
ownership interest in the Applicable Trust, which amount equals the maximum
aggregate principal amount of Equipment Notes which may be purchased by the
Trustee pursuant to the Note Purchase Agreement. Except as provided in Sections
3.03, 3.04, 3.05 and 3.06 of the Basic Agreement, the Trustee shall not execute,
authenticate or deliver Applicable Certificates in excess of the aggregate
amount specified in this paragraph.

<PAGE>

            (b) On or after the Issuance Date the Company may deliver from time
to time to the Trustee a Closing Notice relating to one or more Equipment Notes.
After receipt of a Closing Notice and in any case no later than one Business Day
prior to a Delivery Date as to which such Closing Notice relates (the
"Applicable Delivery Date"), the Trustee shall (as and when specified in the
Closing Notice) instruct the Escrow Agent to provide a Notice of Purchase
Withdrawal to the Depositary requesting (A) the withdrawal of one or more
Deposits on the Applicable Delivery Date in accordance with and to the extent
permitted by the terms of the Escrow Agreement and the Deposit Agreement and (B)
the payment of all, or a portion, of such Deposit or Deposits in an amount equal
in the aggregate to the purchase price of such Equipment Notes to or on behalf
of the Owner Trustee or the Company, as the case may be, issuing such Equipment
Notes, all as shall be described in the Closing Notice. The Trustee shall (as
and when specified in such Closing Notice), subject to the conditions set forth
in Section 3 of the Note Purchase Agreement, enter into and perform its
obligations under the Participation Agreement specified in such Closing Notice
(the "Applicable Participation Agreement") and cause such certificates,
documents and legal opinions relating to the Trustee to be duly delivered as
required by the Applicable Participation Agreement. If at any time prior to the
Applicable Delivery Date, the Trustee receives a notice of postponement pursuant
to Section 2(e), 2(f), or 2(g) of the Note Purchase Agreement, then the Trustee
shall give the Depositary (with a copy to the Escrow Agent) a notice of
cancellation of such Notice of Purchase Withdrawal relating to such Deposit or
Deposits on such Applicable Delivery Date. Upon satisfaction of the conditions
specified in the Note Purchase Agreement and the Applicable Participation
Agreement, the Trustee shall purchase the applicable Equipment Notes with the
proceeds of the withdrawals of one or more Deposits made on the Applicable
Delivery Date in accordance with the terms of the Deposit Agreement and the
Escrow Agreement. The purchase price of such Equipment Notes shall equal the
principal amount of such Equipment Notes. Amounts withdrawn from such Deposit or
Deposits in excess of the purchase price of the Equipment Notes or to the extent
not applied on the Applicable Delivery Date to the purchase price of the
Equipment Notes, shall be re-deposited by the Trustee with the Depositary on the
Applicable Delivery Date in accordance with the terms of the Deposit Agreement.
The provisions of Section 5.01(a) hereof and this Section 5.01(b) supersede and
replace the provisions of Section 2.02 of the Basic Agreement (which are
inapplicable to the Trust), and all provisions of the Basic Agreement relating
to Section 2.02 of the Basic Agreement shall not apply to the Applicable Trust.

            Section 5.02. Withdrawal of Deposits. If any Deposits remain
outstanding on the Business Day next succeeding the Cut-off Date or on the
Termination Date, (i) the Trustee shall give the Escrow Agent notice that the
Trustee's obligation to purchase Equipment Notes under the Note Purchase
Agreement has terminated and instruct the Escrow Agent to provide a notice of
Final Withdrawal to the Depositary substantially in the form of Exhibit B to the
Deposit Agreement (the "Final Withdrawal Notice") and (ii) the Trustee will make
a demand upon the Company under the Note Purchase Agreement for an amount equal
to the Special Redemption Premium, such payment to be made on the Final
Withdrawal Date.

<PAGE>

            Section 5.03. The Trustee. (a) Subject to Section 5.04 of this Trust
Supplement and Section 7.15 of the Basic Agreement, the Trustee shall not be
responsible in any manner whatsoever for or in respect of the validity or
sufficiency of this Trust Supplement, the Deposit Agreement or the Escrow
Agreement or the due execution hereof or thereof by the Company or the other
parties thereto (other than the Trustee), or for or in respect of the recitals
and statements contained herein or therein, all of which recitals and statements
are made solely by the Company.

            (b) Except as herein otherwise provided, no duties, responsibilities
or liabilities are assumed, or shall be construed to be assumed by the Trustee
by reason of this Trust Supplement other than as set forth in the Basic
Agreement, and this Trust Supplement is executed and accepted on behalf of the
Trustee, subject to all the terms and conditions set forth in the Basic
Agreement, upon the effectiveness thereof, as fully to all intents as if the
same were herein set forth at length.

            Section 5.04. Representations and Warranties of the Trustee. The
Trustee hereby represents and warrants that:

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

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

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

<PAGE>

            (d) this Trust Supplement, the Intercreditor Agreement, the
      Registration Agreement, the Escrow Agreement and the Note Documents to
      which it is a party have been, or will be, as applicable, duly executed
      and delivered by the Trustee and constitute, or will constitute, as
      applicable, the legal, valid and binding agreements of the Trustee,
      enforceable against it in accordance with their respective terms;
      provided, however, that enforceability may be limited by (i) applicable
      bankruptcy, insolvency, reorganization, moratorium or similar laws
      affecting the rights of creditors generally and (ii) general principles of
      equity.

            Section 5.05. Trustee Liens. The Trustee in its individual capacity
agrees, in addition to the agreements contained in Section 7.17 of the Basic
Agreement, that it will at its own cost and expense promptly take any action as
may be necessary to duly discharge and satisfy in full any Trustee's Liens on or
with respect to the Trust Property which is attributable to the Trustee in its
individual capacity and which is unrelated to the transactions contemplated by
the Intercreditor Agreement or the Note Purchase Agreement.

                                   ARTICLE VI
                             SUPPLEMENTAL AGREEMENTS

            Section 6.01. Supplemental Agreements Without Consent of Applicable
Certificateholders. Under the terms of, and subject to the limitations contained
in, Section 9.01 of the Basic Agreement, the Company may (but will not be
required to), and the Trustee (subject to Section 9.03 of the Basic Agreement)
shall, at the Company's request, at any time and from time to time, enter into
one or more agreements supplemental to the Escrow Agreement, the Note Purchase
Agreement or the Deposit Agreement, for any of the purposes set forth in clauses
(1) through (9) of such Section 9.01, except that (a) clause (3) of such Section
9.01 shall be deemed to include the Company's rights and powers conferred by the
Note Purchase Agreement and (b) clause (4) of such Section 9.01 shall be deemed
to include corrections or supplements to provisions of the Escrow Agreement or
the Deposit Agreement which may be defective or inconsistent with any other
provision of this Agreement or contained in any agreement referred to in such
clause (4) and the curing of any ambiguity or the modification of any other
provision with respect to matters or questions arising under the Escrow
Agreement or the Deposit Agreement.

            Section 6.02. Supplemental Agreements with Consent of Applicable
Certificateholders. The provisions of Section 9.02 of the Basic Agreement shall
apply to agreements or amendments for the purpose of adding any provisions to or
changing in any manner or eliminating any of the provisions of the Escrow
Agreement, the Deposit Agreement or the Note Purchase Agreement to the extent
applicable to the Applicable Certificateholders approving such agreement or
amendment or modifying in any manner the rights and obligations of such
Applicable Certificateholders under the Escrow Agreement, the Deposit Agreement
or the Note Purchase Agreement; provided that the provisions of Section 9.02(1)
of the Basic Agreement shall be deemed to include reductions in any manner of,
or delay in the timing of, any receipt by the Applicable Certificateholders of
payments upon the Deposits. The provisions of Sections 9.01(9) and 9.01(10) of
the Basic Agreement shall not be applicable to this Trust Supplement.

<PAGE>

                                   ARTICLE VII
                              TERMINATION OF TRUST

            Section 7.01. Termination of the Trust. The respective obligations
and responsibilities of the Company and the Trustee with respect to the
Applicable Trust shall terminate upon the distribution to all Applicable
Certificateholders and the Trustee of all amounts required to be distributed to
them pursuant to this Agreement and the disposition of all property held as part
of the Trust Property; provided, however, that in no event shall the Applicable
Trust continue beyond 21 years less one day following the death of the last
survivor of all descendants living on the date hereof of Joseph P. Kennedy, Sr.,
unless applicable law shall permit a longer term, in which case such longer term
shall apply.

            Notice of any termination specifying the Distribution Date upon
which the Applicable Certificateholders may surrender their Applicable
Certificates to the Trustee for payment of the final distribution and
cancellation, shall be mailed promptly by the Trustee to Applicable
Certificateholders not earlier than the 60th day and not later than the 15th day
next preceding such final Distribution Date specifying (A) the Distribution Date
upon which the proposed final payment of the Applicable Certificates will be
made upon presentation and surrender of Applicable Certificates at the office or
agency of the Trustee therein specified, (B) the amount of any such proposed
final payment, and (C) that the Record Date otherwise applicable to such
Distribution Date is not applicable, payments being made only upon presentation
and surrender of the Applicable Certificates at the office or agency of the
Trustee therein specified. The Trustee shall give such notice to the Registrar
at the time such notice is given to Applicable Certificateholders. Upon
presentation and surrender of the Applicable Certificates in accordance with
such notice, the Trustee shall cause to be distributed to Applicable
Certificateholders such final payments.

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

<PAGE>

                                  ARTICLE VIII
                                   THE COMPANY

            Section 8.01. Consolidation, Mergers, Etc. Section 5.02 of the Basic
Agreement is hereby amended with respect to the Applicable Trust by deleting the
word "and" at the end of clause (b) thereof, renumbering clause (c) as clause
"(d)" and inserting a new clause (c) as follows:

            "(c) immediately after giving effect to such transaction, no
      Indenture Event of Default (in the case of an Owned Aircraft) or, in the
      case of a Leased Aircraft, Lease Event of Default (as defined in the
      related Indenture) shall have occurred and be continuing; and"

                                   ARTICLE IX
                            MISCELLANEOUS PROVISIONS

            Section 9.01. Basic Agreement Ratified. Except and so far as herein
expressly provided, all of the provisions, terms and conditions of the Basic
Agreement are in all respects ratified and confirmed; and the Basic Agreement
and this Trust Supplement shall be taken, read and construed as one and the same
instrument.

            Section 9.02. GOVERNING LAW. THIS AGREEMENT AND THE APPLICABLE
CERTIFICATES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
THE STATE OF NEW YORK.

            Section 9.03. Execution in Counterparts. This Trust Supplement may
be executed in any number of counterparts, each of which shall be an original,
but such counterparts shall together constitute but one and the same instrument.

            Section 9.04. Intention of Parties. The parties hereto intend that
the Applicable Trust be classified for U.S. federal income tax purposes as a
grantor trust under Subpart E, Part I of Subchapter J of the Internal Revenue
Code of 1986, as amended, and not as a trust or association taxable as a
corporation or as a partnership. Each Applicable Certificateholder and Investor,
by its acceptance of its Applicable Certificate or a beneficial interest
therein, agrees to treat the Applicable Trust as a grantor trust for all U.S.
federal, state and local income tax purposes. The powers granted and obligations
undertaken pursuant to the Agreement shall be so construed so as to further such
intent.

            Section 9.05. Benefits of Agreement. (a) Nothing in this Agreement
or in the Certificates of any series, express or implied, shall give to any
person, other than the parties hereto and their successors hereunder and the
Certificateholders of each series, any benefit or any legal or equitable right,
remedy or claim under this Agreement.

            (b) This Section 9.05 supercedes and replaces Section 12.10 of the
Basic Agreement.

<PAGE>

                                    ARTICLE X
                                THE CERTIFICATES

            Section 10.01. Additions to Article III of the Basic Agreement. In
addition to the provisions of Article III of the Basic Agreement, the following
provisions shall apply to the Applicable Trust:

            (a) Initial Certificates offered and sold in reliance on Rule 144A
or to an Institutional Accredited Investor, or resold in reliance on Regulation
S and Rule 904 under the Securities Act, each shall be issued initially in the
form of one or more permanent global Certificates in registered form,
substantially in the form set forth as Exhibit A (respectively, the "144A Global
Certificate," the "IAI Global Certificate," and the "Regulation S Global
Certificate," each, a "Global Certificate"), duly executed and authenticated by
the Trustee as provided in Section 3.02 of the Basic Agreement. The Global
Certificates shall be registered in the name of Cede & Co., as nominee for DTC,
and deposited with the Trustee, as custodian for DTC. The aggregate principal
amount of the Global Certificates may from time to time be decreased by
adjustments made on the records of DTC or its nominee, or of the Trustee, as
custodian for DTC or its nominee, as hereinafter provided.

            (b) Initial Certificates offered and sold other than pursuant to
Rule 144A or pursuant to Regulation S or to Institutional Accredited Investors
shall be issued in the form of permanent certificated Certificates in registered
form, in substantially the form set forth as Exhibit A (the "Physical
Certificates"). All other Certificates shall be Global Certificates.

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

            Section 10.02 Restrictive Legends. (a) Subject to Section 10.03(a)
of this Trust Supplement, unless and until (i) an Initial Certificate or a
Private Exchange Certificate is sold under an effective Registration Statement,
(ii) an Initial Certificate is exchanged for an Exchange Certificate pursuant to
an effective Exchange Offer Registration Statement, (iii) an Initial Certificate
or a Private Exchange Certificate is sold pursuant to Rule 144, (iv) as
otherwise provided in the Private Placement Legend or (v) the Company and the
holder thereof otherwise agree, in each case as provided for in the Registration
Agreement, each Global Certificate and each Physical Certificate shall bear the
following legend (the "Private Placement Legend") on the face thereof:

      THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS AND
ACCORDINGLY, THIS CERTIFICATE OR ANY INTEREST OR PARTICIPATION HEREIN MAY NOT BE
OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT
OF, ANY PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF, THE HOLDER: (1) REPRESENTS THAT (A) IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT), (B) IT
IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501 (a)(1), (2),
(3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT) (AN "INSTITUTIONAL
ACCREDITED INVESTOR"), OR (C) IT IS OTHERWISE ACQUIRING THIS CERTIFICATE IN A
TRANSACTION EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT; (2)
AGREES THAT IT WILL NOT WITHIN TWO YEARS AFTER THE LATER OF THE ORIGINAL
ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE WAS
OWNED BY US AIRWAYS, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY SUCH PERSON
RESELL OR OTHERWISE TRANSFER THIS CERTIFICATE EXCEPT (A) TO US AIRWAYS, INC, (B)
TO A PERSON WHO THE HOLDER REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL
BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C) TO AN

<PAGE>

INSTITUTIONAL ACCREDITED INVESTOR ACQUIRING $100,000 OR MORE AGGREGATE PRINCIPAL
AMOUNT OF SUCH CERTIFICATE THAT, PRIOR TO SUCH TRANSFER, FURNISHED TO THE
TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS CERTIFICATE (THE FORM OF WHICH
LETTER CAN BE OBTAINED FROM THE TRUSTEE), (D) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), (E)
IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE SECURITIES ACT OR (F) PURSUANT TO
AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT; AND (3) AGREES
THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS CERTIFICATE IS TRANSFERRED
(OTHER THAN PURSUANT TO CLAUSES (2)(D) AND (2)(F) ABOVE) A NOTICE SUBSTANTIALLY
TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF THIS
CERTIFICATE AS A RESTRICTED SECURITY WITHIN TWO YEARS AFTER THE LATER OF THE
ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE
WAS HELD BY US AIRWAYS, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY SUCH PERSONS
THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE TRANSFER NOTICE
RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE
TRUSTEE; PROVIDED THAT THE COMPANY AND THE TRUSTEE SHALL HAVE THE RIGHT PRIOR TO
ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSE (2)(C) OR (2)(E) TO REQUIRE
THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION
SATISFACTORY TO EACH OF THEM. THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF
THE HOLDER AFTER THE RESALE RESTRICTIONS TERMINATE. THE CLASS C TRUST SUPPLEMENT
CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF
THIS CERTIFICATE IN VIOLATION OF THE FOREGOING RESTRICTIONS.

            (b) Each Global Certificate of each class shall also bear the
following legend on the face thereof:

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

      TRANSFERS OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO TRANSFERS IN
      WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR
      SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL
      CERTIFICATE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
      RESTRICTIONS SET FORTH IN SECTION 10.03 OF THE TRUST SUPPLEMENT NO.
      2000-3C.

            Section 10.03. Special Transfer Provisions. Unless and until (i) an
Initial Certificate or a Private Exchange Certificate is sold under an effective
Registration Statement, (ii) an Initial Certificate is exchanged for an Exchange
Certificate pursuant to an effective Exchange Offer Registration Statement,
(iii) an Initial Certificate or a Private Exchange Certificate is sold pursuant
to Rule 144, (iv) as otherwise provided in the Private Placement Legend or (v)
the Company and the holder thereof otherwise agree, the Registrar shall refuse
to register any exchange except in accordance with the following provisions:

            (a) Private Placement Legend. Upon the transfer, exchange or
replacement of Applicable Certificates not bearing the Private Placement Legend,
the Registrar shall deliver Applicable Certificates that do not bear the Private
Placement Legend. Upon the transfer, exchange or replacement of Applicable
Certificates bearing the Private Placement Legend, the Registrar shall deliver
only Applicable Certificates that bear the Private Placement Legend, except as
contemplated by Section 10.02.

<PAGE>

            (b) General. By its acceptance of any Applicable Certificate bearing
the Private Placement Legend, each Holder of such Applicable Certificate
acknowledges the restrictions on transfer of such Applicable Certificate set
forth in this Trust Supplement and agrees that it shall transfer such
Certificate only as provided in this Trust Supplement. The Registrar shall not
register a transfer of any Applicable Certificate unless such transfer complies
with the restrictions on transfer of such Certificate set forth in this Trust
Supplement. In connection with any transfer of Applicable Certificates, each
Certificateholder agrees by its acceptance of the Applicable Certificates to
furnish the Registrar or the Trustee such certifications, legal opinions or
other information as the Private Placement Legend requires to confirm that such
transfer is being made pursuant to an exemption from, or a transaction not
subject to, the registration requirements of the Securities Act.

            Until such time as no Applicable Certificates remain Outstanding,
the Registrar shall retain copies of all letters, notices and other written
communications received pursuant to this Section 10.03. The Trustee, if not the
Registrar at such time, shall have the right to inspect and make copies of all
such letters, notices or other written communications at any reasonable time
upon the giving of reasonable written notice to the Registrar.

            Transfers of the Applicable Certificates (and interests therein)
among different types of Global Certificates (including a Global Certificate not
containing a Private Placement Legend) and from Global Certificates to a
Physical Certificate and from Physical Certificates to Global Certificates shall
be made in accordance with the procedures set forth on Exhibit F hereto.

            IN WITNESS WHEREOF, the Company and the Trustee have caused this
Trust Supplement to be duly executed by their respective officers thereto duly
authorized, as of the day and year first written above.

                                  US AIRWAYS, INC.

                                  By:       /s/ Jeffery A. McDougle
                                      ----------------------------------------
                                      Name: Jeffery A. McDougle
                                      Title: Vice President and Treasurer

                                  STATE STREET BANK AND TRUST
                                  COMPANY OF CONNECTICUT,
                                  NATIONAL ASSOCIATION, as Trustee

                                  By:       /s/ John G. Correia
                                      ----------------------------------------
                                      Name: John G. Correia
                                      Title: Assistant Vice President

<PAGE>

                                    EXHIBIT A

                               FORM OF CERTIFICATE

      THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS AND
ACCORDINGLY, THIS CERTIFICATE OR ANY INTEREST OR PARTICIPATION HEREIN MAY NOT BE
OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT
OF, ANY PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF, THE HOLDER: (1) REPRESENTS THAT (A) IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT), (B) IT
IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501 (a)(1), (2),
(3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT) (AN "INSTITUTIONAL
ACCREDITED INVESTOR"), OR (C) IT IS OTHERWISE ACQUIRING THIS CERTIFICATE IN A
TRANSACTION EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT; (2)
AGREES THAT IT WILL NOT WITHIN TWO YEARS AFTER THE LATER OF THE ORIGINAL
ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE WAS
OWNED BY US AIRWAYS, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY SUCH PERSON
RESELL OR OTHERWISE TRANSFER THIS CERTIFICATE EXCEPT (A) TO US AIRWAYS, INC.,
(B) TO A PERSON WHO THE HOLDER REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL
BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C) TO AN
INSTITUTIONAL ACCREDITED INVESTOR ACQUIRING $100,000 OR MORE AGGREGATE PRINCIPAL
AMOUNT OF SUCH CERTIFICATE THAT, PRIOR TO SUCH TRANSFER, FURNISHED TO THE
TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS CERTIFICATE (THE FORM OF WHICH
LETTER CAN BE OBTAINED FROM THE TRUSTEE), (D) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), (E)
IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE SECURITIES ACT OR (F) PURSUANT TO
AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT; AND (3) AGREES
THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS CERTIFICATE IS TRANSFERRED
(OTHER THAN PURSUANT TO CLAUSES (2)(D) AND (2)(F) ABOVE) A NOTICE SUBSTANTIALLY
TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF THIS
CERTIFICATE AS A RESTRICTED SECURITY WITHIN TWO YEARS AFTER THE LATER OF THE
ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE
WAS HELD BY US AIRWAYS, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY SUCH PERSONS
THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE TRANSFER NOTICE
RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE
TRUSTEE; PROVIDED THAT THE COMPANY AND THE TRUSTEE SHALL HAVE THE RIGHT PRIOR TO
ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSE (2)(C) OR (2)(E) TO REQUIRE
THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION
SATISFACTORY TO EACH OF THEM. THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF
THE HOLDER AFTER THE RESALE RESTRICTIONS TERMINATE. THE CLASS C TRUST SUPPLEMENT
CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF
THIS CERTIFICATE IN VIOLATION OF THE FOREGOING RESTRICTIONS.

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

<PAGE>

      TRANSFERS OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO TRANSFERS IN
WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH
SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL CERTIFICATE SHALL
BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
SECTION 10.03 OF THE TRUST SUPPLEMENT NO. 2000-3C

                  US AIRWAYS SERIES 2000-3C PASS THROUGH TRUST

                        8.39% US Airways [Initial][Exchange]
                        Pass Through Certificate, Series
                        2000-3C

                        Final Expected Regular Distribution
                        Date: March 1, 2022 evidencing a
                        fractional undivided interest in a
                        trust, the property of which
                        includes certain equipment notes
                        each secured by Aircraft owned by or
                        leased to US Airways, Inc.

Certificate
No.1                    $157,054,000 Fractional Undivided Interest representing

--------
*This legend to appear on Book-Entry Certificates to be deposited with The
Depository Trust Company.

<PAGE>

                .0006367237% of the Trust per $1,000 face amount

            THIS CERTIFIES THAT Cede & Co., for value received, is the
registered owner of a $157,054,000 (ONE HUNDRED FIFTY SEVEN MILLION FIFTY FOUR
THOUSAND dollars) Fractional Undivided Interest in the US Airways Pass Through
Trust, Series 2000-3C (the "Trust") created by State Street Bank and Trust
Company of Connecticut, National Association, as trustee (the "Trustee"),
pursuant to a Pass Through Trust Agreement dated as of October 5, 2000 (the
"Basic Agreement"), between the Trustee and US Airways, Inc., a Delaware
corporation (the "Company"), as supplemented by Trust Supplement No. 2000-3C
thereto dated November 2, 2000, between the Trustee and the Company
(collectively, the "Agreement"), a summary of certain of the pertinent
provisions of which is set forth below. To the extent not otherwise defined
herein, the capitalized terms used herein have the meanings assigned to them in
the Agreement. This Certificate is one of the duly authorized Certificates
designated as "8.39% US Airways [Initial][Exchange] Pass Through Certificate,
Series 2000-3C" (herein called the "Certificates"). This Certificate is issued
under and is subject to the terms, provisions and conditions of the Agreement.
By virtue of its acceptance hereof, the Certificateholder of this Certificate
assents to and agrees to be bound by the provisions of the Agreement and the
Intercreditor Agreement. The property of the Trust includes certain Equipment
Notes and all rights of the Trust to receive any payments under the
Intercreditor Agreement and any Liquidity Facility (the "Trust Property"). Each
issue of the Equipment Notes is or will be secured by, among other things, a
security interest in aircraft leased to or owned by the Company.

            The Certificates represent Fractional Undivided Interests in the
Trust and the Trust Property, and have no rights, benefits or interest in
respect of any other separate trust established pursuant to the terms of the
Basic Agreement for any other series of certificates issued pursuant thereto.

            Subject to and in accordance with the terms of the Agreement and the
Intercreditor Agreement, from funds then available to the Trustee, there will be
distributed on each March 1 and September 1 (a "Regular Distribution Date"),
commencing on March 1, 2001, to the Person in whose name this Certificate is
registered at the close of business on the 15th day preceding the Regular
Distribution Date, an amount in respect of the Scheduled Payments on the
Equipment Notes due on such Regular Distribution Date, the receipt of which has
been confirmed by the Trustee, equal to the product of the percentage interest
in the Trust evidenced by this Certificate and an amount equal to the sum of
such Scheduled Payments. Subject to and in accordance with the terms of the
Agreement and the Intercreditor Agreement, in the event that Special Payments on
the Equipment Notes are received by the Trustee, from funds then available to
the Trustee, there shall be distributed on the applicable Special Distribution
Date, to the Person in whose name this Certificate is registered at the close of
business on the 15th day preceding the Special Distribution Date, an amount in
respect of such Special Payments on the Equipment Notes, the receipt of which
has been confirmed by the Trustee, equal to the product of the percentage
interest in the Trust evidenced by this Certificate and an amount equal to the
sum of such Special Payments so received. If a Regular Distribution Date or
Special Distribution Date is not a Business Day, distribution shall be made on
the immediately following Business Day with the same force and effect as if made
on such Regular Distribution Date or Special Distribution Date and no interest
shall accrue during the intervening period. The Trustee shall mail notice of
each Special Payment and the Special Distribution Date therefor to the
Certificateholder of this Certificate.

<PAGE>

            The Holder of this Certificate is entitled to the benefits of the
Registration Agreement, dated as of November 2, 2000, between the Company, the
Trustee and the Purchaser named therein (the "Registration Agreement"). If (i)
any Registration Statement required by the Registration Agreement is not (i)
filed with the Securities and Exchange Commission (the "Commission") on or prior
to the applicable filing deadline specified in the Registration Agreement, (ii)
any Registration Statement required by the Registration Agreement is not
declared effective by the Commission on or prior to the applicable effectiveness
deadline specified in the Registration Agreement, (iii) any Registered Exchange
Offer has not been consummated on or prior to the consummation deadline
specified in the Registration Agreement or (iv) any Registration Statement
required by the Registration Agreement is filed and declared effective but shall
thereafter cease to be effective or fail to be usable for its intended purpose
at any time prior to (a) in the case of an Exchange Offer Registration
Statement, the expiration of the respective Exchange Offer Registration Period
(as defined in the Registration Agreement) or (b) if a Shelf Registration
Statement (as defined in the Registration Agreement) is required to be filed
pursuant to the Registration Agreement, the expiration of the Shelf Registration
Period (as defined in the Registration Agreement), in each case without being
succeeded within two (2) days by a post-effective amendment to such Registration
Statement that cures such failure and that is itself declared effective within
five (5) days of filing such post-effective amendment to such Registration
Statement (each such event in clauses (i) through (iv), a "Registration
Default"), then the interest rate applicable to this Certificate shall be
increased as follows: during the first ninety (90)-day period immediately
following the occurrence of such Registration Default, such interest rate shall
be increased by 0.25% per annum from and including the first Business Day
following the date on which such Registration Default occurs to but excluding
the date such Registration Default is cured in accordance with the last sentence
of this paragraph. During Each subsequent ninety (90) day period during which
any Registration Default has occurred and is continuing, the interest rate
applicable to this Certificate shall increase by an additional 0.25% per annum
up to a maximum of 1.00% per annum. Notwithstanding the foregoing, (1) upon the
filing of the respective Registered Exchange Offer Registration Statement
(and/or, if applicable, the Shelf Registration Statement), in the case of (i)
above, (2) upon the effectiveness of the respective Registered Exchange Offer
Registration Statement (and/or, if applicable, the Shelf Registration Statement)
in the case of (ii) above, (3) upon consummation of the respective Registered
Exchange Offer in the case of (iii) above, or (4) upon the filing of a
post-effective amendment to the respective Registration Statement or any
additional Registration Statement that causes the respective Exchange Offer
Registration Statement (and/or, if applicable, the Shelf Registration Statement)
to again be declared effective or made usable in the case of (iv) above, the
existing Registration Default shall be deemed cured and the Securities that are
the subject of such Registration Statement as a result of such clause (i), (ii),
(iii) or (iv), as applicable, will again bear interest at 8.39% per annum, until
such time, if any, that another Registration Default occurs. Notwithstanding any
other provision of the Registration Agreement, the time periods in which a
Registration Default will be deemed to have occurred may be delayed or extended
in accordance with the provisions of the Registration Agreement.

            Subject to the terms of the Intercreditor Agreement, any incremental
interest due to a Holder of this Certificate will be passed through to such
Holder on each Regular Distribution Date in the manner provided for in the
Agreement, as more fully set forth in the Agreement and this Certificate.

<PAGE>

            Distributions on this Certificate will be made by the Trustee by
check mailed to the Person entitled thereto, without the presentation or
surrender of this Certificate or the making of any notation hereon, except that
with respect to Certificates registered on the Record Date in the name of a
Clearing Agency (or its nominee), such distribution shall be made by wire
transfer. Except as otherwise provided in the Agreement and notwithstanding the
above, the final distribution on this Certificate will be made after notice
mailed by the Trustee of the pendency of such distribution and only upon
presentation and surrender of this Certificate at the office or agency of the
Trustee specified in such notice.

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

            The Agreement permits, with certain exceptions therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Certificateholders under the Agreement at any time
by the Company and the Trustee with the consent of the Certificateholders
holding Certificates evidencing Fractional Undivided Interests aggregating not
less than a majority in interest in the Trust. Any such consent by the
Certificateholder of this Certificate shall be conclusive and binding on such
Certificateholder and upon all future Certificateholders of this Certificate and
of any Certificate issued upon the transfer hereof or in exchange hereof or in
lieu hereof whether or not notation of such consent is made upon this
Certificate. The Agreement also permits the amendment thereof, in certain
limited circumstances, without the consent of the Certificateholders of any of
the Certificates.

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

<PAGE>

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

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

            Each Certificateholder and Investor, by its acceptance of this
Certificate or a beneficial interest herein, agrees to treat the Trust as a
grantor trust for all U.S. federal, state and local income tax purposes.

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

            The obligations and responsibilities created by the Agreement and
the Trust created thereby shall terminate upon the distribution to
Certificateholders of all amounts required to be distributed to them pursuant to
the Agreement and the disposition of all property held as part of the Trust
Property.

            Any Person acquiring or accepting this Certificate or an interest
herein will, by such acquisition or acceptance, be deemed to have represented
and warranted that either: (i) the assets of an employee benefit plan subject to
Title I of the Employee Retirement Income Security Act of 1974, as amended
("ERISA"), or of a plan subject to Section 4975 of the Internal Revenue Code of
1986, as amended (the "Code"), have not been used to purchase this Certificate
or an interest herein or (ii) the purchase and holding of this Certificate or
interest herein are exempt from the prohibited transaction restrictions of ERISA
and the Code pursuant to one or more prohibited transaction statutory or
administrative exemptions.

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

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

<PAGE>

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

                                              US AIRWAYS PASS THROUGH TRUST
                                              2000-3C
                                              By: STATE STREET BANK AND TRUST
                                              COMPANY OF CONNECTICUT,
                                              NATIONAL ASSOCIATION, as Trustee

                                              By: ______________________________
                                              Title: ___________________________

Dated: ______________________________

<PAGE>

               FORM OF THE TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

                                           STATE STREET BANK AND TRUST
                                           COMPANY OF CONNECTICUT,
                                           NATIONAL ASSOCIATION, as Trustee

                                           By: _________________________________
                                                   Authorized Officer

<PAGE>

                                    EXHIBIT B

                             FORM OF TRANSFER NOTICE

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

Insert Taxpayer Identification No.

___________________

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

___________________

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

___________________

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

            In connection with any transfer of this Certificate occurring prior
to the date that is the earlier of the date of an effective Registration
Statement or ________, ____, the undersigned confirms that without utilizing any
general solicitation or general advertising that:

                                   [Check One]

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

                                       or

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

            If neither of the foregoing boxes is checked, the Trustee or other
Registrar shall not be obligated to register this Certificate in the name of any
Person other than the Holder hereof unless and until the conditions to any such
transfer of registration set forth herein and in Section 10.03 of the Trust
Supplement shall have been satisfied.

Date:                                [Name of Transferor]

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

Signature Guarantee: ___________________________

<PAGE>

                                    EXHIBIT C

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

                                                                          [Date]

State Street Bank and Trust Company
      of Connecticut, National Association
[Address]

      Re:   US Airways Pass Through Trust 2000-3C (the "Trust"), US Airways Pass
            Through Certificates, Series 2000-3C (the "Certificates")

Dear Sirs:

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

1.          the offer of the Certificates was not made to a person in the United
            States;

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

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

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

            In addition, if the sale is made during a restricted period and the
provisions of Rule 903(c)(3) or Rule 904(c)(1) of Regulation S are applicable
thereto, we confirm that such sale has been made in accordance with the
applicable provisions of Rule 903(c)(3) or Rule 904(c)(1), as the case may be.

            You and US Airways, Inc. are entitled to rely upon this letter and
are irrevocably authorized to produce this letter or a copy hereof to any
interested party in any administrative or legal proceedings or official inquiry
with respect to the matters covered hereby. Terms used in this certificate have
the meanings set forth in Regulation S.

                                               Very truly yours,
                                               [Name of Transferor]

                                                By: ____________________________
                                                    Authorized Signature

<PAGE>

                                    EXHIBIT D

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

                                                                          [Date]

State Street Bank and Trust Company of Connecticut,
       National Association
[Address]

      Re:   US Airways Pass Through Trust 2000-3C (the "Trust"), US Airways Pass
            Through Certificates, Series 2000-3C (the "Certificates")

Dear Sirs:

            In connection with our proposed purchase of $_________ aggregate
principal amount of the Certificates, we confirm that:

1.          We understand that any subsequent transfer of the Certificates is
            subject to certain restrictions and conditions set forth in the Pass
            Through Trust Agreement, dated as of __________, 2000, as
            supplemented by Trust Supplement No. 2000-3C, relating to the
            Certificates (the "Pass Through Trust Agreement") and the
            undersigned agrees to be bound by, and not to resell, pledge or
            otherwise transfer the Certificates except in compliance with, such
            restrictions and conditions and the Securities Act of 1933, as
            amended (the "Securities Act").

2.          We understand that the Certificates have not been registered under
            the Securities Act, and that the Certificates may not be offered or
            sold except as permitted in the following sentence. We agree, on our
            own behalf and on behalf of any accounts for which we are acting as
            hereinafter stated, that if we should sell any Certificate, we shall
            do so only (A) to US Airways, Inc., (B) to a person who the holder
            reasonably believes is a "qualified institutional buyer" in
            compliance with Rule 144A under the Securities Act, (C) to an
            institutional "accredited investor" acquiring $100,000 or more
            aggregate principal amount of such Certificate that, prior to such
            transfer, furnished to the Trustee a signed letter containing
            certain representations and agreements relating to the restrictions
            on transfer of this certificate (the form of which letter can be
            obtained from the Trustee), (D) pursuant to the exemption from
            registration provided by Rule 144 under the Securities Act (if
            available), (E) in accordance with another exemption from the
            Securities Act or (F) pursuant to an effective registration
            statement under the Securities Act; and we further agree to provide
            to any person purchasing any of the Certificates from us a notice
            advising such purchaser that resales of the Notes are restricted as
            stated herein. We further understand that the Certificates purchased
            by us shall bear a legend to the foregoing effect.

<PAGE>

3.          We understand that, in connection with any transfer of this
            Certificate as a restricted security within two years after the
            later of the original issuance of this Certificate or the last date
            on which this Certificate was held by US Airways, Inc., the Trustee,
            or any affiliate of any such persons, the holder must check the
            appropriate box set forth on the transfer notice attached to the
            Certificate relating to the manner of such transfer and submit this
            Certificate to the Trustee; provided that the Company and the
            Trustee shall have the right prior to any such offer, sale or
            transfer pursuant to clause (C) or (E) in paragraph 2 to require the
            delivery of an opinion of counsel, certification and/or other
            information satisfactory to each of them. We further understand that
            the Certificates purchased by us shall bear a legend to the
            foregoing effect.

4.          We are [an institutional "accredited investor" (as defined in Rule
            501(a)(1), (2), (3) or (7)]*/[a non-institutional "accredited
            investor" (as defined in Rule 501(a), (4), (5), (6) or (8)]** of
            Regulation D under the Securities Act) and have such knowledge and
            experience in financial and business matters as to be [, or have
            access to financial, legal, accounting and tax advisors and have
            consulted the same to the extent necessary for us to be,]** capable
            of evaluating the merits and risks of our investment in the
            Certificates and we and any accounts for which we are acting are
            each able to bear the economic risk of our or its investment.

-------
*        For institutional accredited investors only.

**       For non-institutional accredited investors only.

<PAGE>

5.          We are acquiring the Certificates purchased by us for our own
            account [or for one or more accounts (each of which is an
            institutional "accredited investor") as to each of which we exercise
            sole investment discretion.]*

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

                                               Very truly yours,
                                               [Name of Transferee]

                                               By: _____________________________
                                                   Authorized Signature

<PAGE>

                                    EXHIBIT E

                         [DTC Letter of Representations]

<PAGE>

                                    EXHIBIT F

                        OTHER SPECIAL TRANSFER PROVISIONS

      The following provisions shall supplement and, to the extent inconsistent
with, shall supercede and replace Sections 3.04 and 3.05 of the Basic Agreement.

            (a) Transfers other than to QIBs, IAIs, or pursuant to Regulation S.
The following provisions shall apply with respect to the registration of any
proposed transfer of an Applicable Certificate bearing, both before and after
the transfer, a Private Placement Legend (a "Restricted Certificate") other than
to any QIB, IAI which is not a QIB, or pursuant to Regulation S:

                  (i) The Registrar shall register the transfer of any such
      Restricted Certificate, if the proposed transferee has delivered to the
      Registrar a letter substantially in the form of Exhibit D hereto, and if
      (x) the proposed transferee agrees that it will not within two years after
      the later of the original issuance of this certificate or the last date on
      which this certificate was owned by US Airways, Inc., the Trustee or any
      affiliate of any such person resell or otherwise transfer this certificate
      except (a) to US Airways, Inc., (b) to a person who the transferee
      reasonably believes is a Qualified Institutional Buyer in compliance with
      Rule 144A under the Securities Act, (c) to an Institutional Accredited
      Investor acquiring $100,000 or more aggregate principal amount of such
      Certificate that, prior to such transfer, furnished to the Trustee a
      signed letter containing certain representations and agreements relating
      to the restrictions on transfer of this Certificate (the form of which
      letter substantially in the form of Exhibit D), (d) pursuant to the
      exemption from registration provided by Rule 144 under the Securities Act
      (if available), (e) in accordance with another exemption from the
      Securities Act or (f) pursuant to an effective registration statement
      under the Securities Act; (y) the proposed transferee agrees that it will
      deliver to each person to whom this certificate is transferred (other than
      pursuant to clauses (d) and (f) above) a notice substantially to the
      effect of this legend; and (z) the proposed transferor and transferee have
      delivered to the Registrar such other documents as are required by the
      Private Placement Legend.

                  (ii) If the proposed transferor is an Agent Member holding a
      beneficial interest in a Global Certificate, upon receipt by the Registrar
      of (x) the documents, if any, required by paragraph (i) and (y)
      instructions given in accordance with DTC's and the Registrar's
      procedures, the Registrar shall reflect on its books and records the date
      of the transfer and a decrease in the principal amount of such Global
      Certificate in an amount equal to the Fractional Undivided Interest
      represented by the beneficial interest in such Global Certificate to be
      transferred, and the Company shall execute, and the Trustee shall
      authenticate and deliver to the transferor or at its direction, one or
      more Physical Certificates of like class, tenor and amount, or an interest
      in a Restricted Certificate (other than a Rule 144A Global Certificate).

<PAGE>

            (b) Transfers to QIBs. The following provisions shall apply with
respect to the registration of any proposed transfer to a QIB:

                  (i) The Registrar shall register the transfer if (x) such
      transfer is being made by a proposed transferor who has checked the box
      provided for on the Form of Transfer Notice attached to the Initial
      Certificate or Private Exchange Certificate stating, or has otherwise
      advised the Trustee and the Registrar in writing, that the sale has been
      made in compliance with the provisions of Rule 144A to a transferee who
      the transferor reasonably believes is a QIB and has notified the
      transferee that the transferor is relying upon its foregoing
      representations in order to claim the exemption from registration provided
      by Rule 144A; and (y) the proposed transferor and transferee have
      delivered to the Registrar such other documents as are required by the
      Private Placement Legend.

                  (ii) If the Certificate to be transferred is a Physical
      Certificate, upon receipt by the Registrar of the documents referred to in
      clause (i) above and instructions given in accordance with DTC's and the
      Registrar's procedures therefor, the Registrar shall reflect on its books
      and records the date of such transfer and an increase in the Fractional
      Undivided Interest of the Rule 144A Global Certificate in an amount equal
      to the Fractional Undivided Interest of the Physical Certificates being
      transferred, and the Trustee shall cancel such Physical Certificates. If
      the proposed transfer is a transfer of a beneficial interest in one Global
      Certificate, the provisions of paragraph (e) below shall apply.

            (c) Transfers to IAIs. The following provisions shall apply with
respect to the registration of any proposed transfer of, or an interest in, a
Restricted Certificate (other than the IAI Global Certificate) to an IAI who is
not a QIB:

                  (i) The Registrar shall register the transfer if the proposed
      transferee has delivered to the Registrar a letter substantially in the
      form of Exhibit D and the proposed transferor and transferee have
      delivered to the Registrar such other documents as are required by the
      Private Placement Legend.

                  (ii) If the Certificate to be transferred is a Physical
      Certificate, upon receipt by the Registrar of the documents referred to in
      clause (i) above and instructions given in accordance with DTC's and the
      Registrar's procedures therefor, the Registrar shall reflect on its books
      and records the date of such transfer and an increase in the Fractional
      Undivided Interest of the IAI Global Certificate in an amount equal to the
      Fractional Undivided Interest of the Physical Certificates being
      transferred, and the Trustee shall cancel such Physical Certificates. If
      the proposed transfer is a transfer of a beneficial interest in one Global
      Certificate to a beneficial interest in another Global Certificate, the
      provisions of paragraph (e) below shall apply.

            (d) Transfers to Non-U.S. Persons. The following provisions shall
apply with respect to any registration of any transfer of an Initial Certificate
in accordance with Regulation S:

<PAGE>

                  (i) The Registrar shall register any proposed transfer to any
      Non-U.S. Person if the Certificate to be transferred is a Physical
      Certificate or an interest in the Global Certificate, upon receipt of a
      certificate substantially in the form of Exhibit C from the proposed
      transferor. The Registrar shall promptly send a copy of such certificate
      to the Company.

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

                  (iii) Upon a sale or transfer after the expiration of the
      "restricted period" as defined in Regulation S of any Restricted
      Certificate acquired pursuant to Regulation S, such Certificate shall no
      longer bear the Private Placement Legend.

            (e) Transfers of and between Global Certificates. (i) Transfers of
any Global Certificate shall be limited to transfers of such Global Certificate
in whole, but not in part, to nominees of DTC, its successor or such successor's
nominees. Beneficial interests in the Global Certificate may be transferred in
accordance with the rules and procedures of DTC and the provisions of Section
9.03 and this Exhibit F. If the proposed transfer is a transfer of a beneficial
interest in one Global Certificate to a beneficial interest in another Global
Certificate, the Registrar shall reflect on its books and records the date of
such transfer and an increase in the principal amount of the Global Certificate
to which such interest is being transferred in an amount equal to the principal
amount of the interest to be so transferred, and the Registrar shall reflect on
its books and records the date of such transfer and a corresponding decrease in
the principal amount of the Global Certificate from which such interest is being
transferred.<PAGE>

                                                                     EXHIBIT 4.6

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

                       REVOLVING CREDIT AGREEMENT(2000-3C)

                          Dated as of November 2, 2000

                                     between

               STATE STREET BANK AND TRUST COMPANY OF CONNECTICUT,
                              NATIONAL ASSOCIATION
  as Subordination Agent, as agent and trustee for the US Airways Pass Through
                                  Trust 2000-3C

                                   as Borrower

                                       and

           MORGAN STANLEY CAPITAL SERVICES INC., as Liquidity Provider

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

                                   Relating to

                      US Airways Pass Through Trust 2000-3C
                   8.39% US Airways Pass Through Certificates,
                                 Series 2000-3C

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
<S>                                                                         <C>
ARTICLE I  DEFINITIONS....................................................   1
         Section 1.01.  Certain Defined Terms.............................   1

ARTICLE II  AMOUNT AND TERMS OF THE COMMITMENT............................   8
         Section 2.01.  The Advances......................................   8
         Section 2.02.  Making the Advances...............................   8
         Section 2.03.  Fees..............................................  10
         Section 2.04.  Reductions, Increases or Termination of
                        the Maximum Commitment............................  10
         Section 2.05.  Repayments of Interest Advances or the
                        Final Advance.....................................  11
         Section 2.06.  Repayments of Provider Advances...................  11
         Section 2.07.  Payments to the Liquidity Provider Under
                        the Intercreditor Agreement.......................  12
         Section 2.08.  Book Entries......................................  12
         Section 2.09.  Payments from Available Funds Only................  13
         Section 2.10.  Extension of the Expiry Date; Non-Extension
                        Advance...........................................  13

ARTICLE III  OBLIGATIONS OF THE BORROWER..................................  13
         Section 3.01.  Increased Costs...................................  13
         Section 3.02.  Capital Adequacy..................................  14
         Section 3.03.  Payments Free of Deductions.......................  15
         Section 3.05.  Computations......................................  17
         Section 3.06.  Payment on Non-Business Days......................  17
         Section 3.07.  Interest..........................................  17
         Section 3.08.  Replacement of Borrower...........................  18
         Section 3.09.  Funding Loss Indemnification......................  18
         Section 3.10.  Illegality........................................  19

ARTICLE IV  CONDITIONS PRECEDENT..........................................  19
         Section 4.01.  Conditions Precedent to Effectiveness
                        of Section 2.01...................................  19
         Section 4.02.  Conditions Precedent to Borrowing.................  21

ARTICLE V  COVENANTS......................................................  21
         Section 5.01.  Affirmative Covenants of the Borrower.............  21
         Section 5.02.  Negative Covenants of the Borrower................  22

ARTICLE VI  LIQUIDITY EVENTS OF DEFAULT...................................  22
         Section 6.01.  Liquidity Events of Default.......................  22

ARTICLE VII  MISCELLANEOUS................................................  23
         Section 7.01.  Amendments, Etc...................................  23
         Section 7.02.  Notices, Etc......................................  23
         Section 7.03.  No Waiver; Remedies...............................  24
         Section 7.04.  Further Assurances................................  24
         Section 7.05.  Indemnification; Survival of Certain
                        Provisions........................................  24
         Section 7.06.  Liability of the Liquidity Provider...............  25
         Section 7.07.  Costs, Expenses and Taxes.........................  26
         Section 7.08.  Binding Effect; Participations....................  26
         Section 7.09.  Severability......................................  28
         Section 7.10.  GOVERNING LAW.....................................  28
         Section 7.11.  Submission to Jurisdiction; Waiver of Jury
                        Trial; Waiver of Immunity.........................  28
         Section 7.12.  Execution in Counterparts.........................  29
         Section 7.13.  Entirety..........................................  29
         Section 7.14.  Headings..........................................  29
         Section 7.15.  LIQUIDITY PROVIDER'S OBLIGATION TO MAKE ADVANCES..  29

ANNEX I   Interest Advance Notice of Borrowing

ANNEX II  Non-Extension Advance Notice of Borrowing

ANNEX III Downgrade Advance Notice of Borrowing

ANNEX IV  Final Advance Notice of Borrowing

ANNEX V   Notice of Termination

ANNEX VI  Notice of Replacement Subordination Agent

EXHIBIT I Form of Guarantee Agreement
</TABLE>
<PAGE>

                      REVOLVING CREDIT AGREEMENT (2000-3C)

      This REVOLVING CREDIT AGREEMENT (2000-3C) dated as of November 2, 2000,
between STATE STREET BANK AND TRUST COMPANY OF CONNECTICUT, NATIONAL
ASSOCIATION, a national banking association, not in its individual capacity but
solely as Subordination Agent under the Intercreditor Agreement (each as defined
below), as agent and trustee for the Class C Trust (as defined below) (the
"Borrower"), and MORGAN STANLEY CAPITAL SERVICES INC., a corporation organized
under the laws of the State of Delaware (the "Liquidity Provider").

                                   WITNESSETH:

      WHEREAS, pursuant to the Class C Trust Agreement (such term and all other
capitalized terms used in these recitals having the meanings set forth or
referred to in Section 1.01), the Class C Trust is issuing the Class C
Certificates;

      WHEREAS, the Borrower, in order to support the timely payment of a portion
of the interest on the Class C Certificates in accordance with their terms, has
requested the Liquidity Provider to enter into this Agreement, providing in part
for the Borrower to request in specified circumstances that Advances be made
hereunder; and

      WHEREAS, the Liquidity Provider has requested Morgan Stanley Dean Witter &
Co. (the "Guarantor") to enter into a Guarantee Agreement in the form attached
hereto as Exhibit I, providing for the full and unconditional guarantee of the
Liquidity Provider's obligations under this Agreement (the "Guarantee
Agreement").

      NOW, THEREFORE, in consideration of the premises, the parties hereto agree
as follows:

                                    ARTICLE I

                                   DEFINITIONS

      Section 1.01. Certain Defined Terms. (a) Definitions. As used in this
Agreement and unless otherwise expressly indicated, or unless the context
clearly requires otherwise, the following capitalized terms shall have the
following respective meanings for all purposes of this Agreement:

      "Additional Cost" has the meaning assigned to such term in Section 3.01.

      "Advance" means an Interest Advance, a Final Advance, a Provider Advance,
an Applied Provider Advance or an Unpaid Advance, as the case may be.

      "Applicable Liquidity Rate" has the meaning assigned to such term in
Section 3.07(f).

      "Applicable Margin" means (x) with respect to any Unpaid Advance or
Applied Provider Advance, 2.0% per annum and (y) with respect to

<PAGE>

any Unapplied Provider Advance, the rate per annum specified in the Liquidity
Facility Fee Letter applicable to this Agreement.

      "Applied Downgrade Advance" has the meaning assigned to such term in
Section 2.06(a).

      "Applied Non-Extension Advance" has the meaning assigned to such term in
Section 2.06(a).

      "Applied Provider Advance" has the meaning assigned to such term in
Section 2.06(a).

      "Base Rate" means a fluctuating interest rate per annum in effect from
time to time, which rate per annum shall at all times be equal to (a) the
weighted average of the rates on overnight Federal funds transactions with
members of the Federal Reserve System arranged by Federal funds brokers, as
published for such day (or, if such day is not a Business Day, for the next
preceding Business Day) by the Federal Reserve Bank of New York, or if such rate
is not so published for any day that is a Business Day, the average of the
quotations for such day for such transactions received by the Liquidity Provider
from three Federal funds brokers of recognized standing selected by it, plus (b)
one quarter of one percent (1/4 of 1%) per annum.

      "Base Rate Advance" means an Advance that bears interest at a rate based
upon the Base Rate.

      "Borrower" has the meaning assigned to such term in the recital of parties
to this Agreement.

      "Borrowing" means the making of Advances requested by delivery of a Notice
of Borrowing.

      "Business Day" means any day other than a Saturday or Sunday or other day
on which insurance companies or commercial banks in New York, New York, or
commercial banking institutions in Pittsburgh, Pennsylvania and in the cities in
which the Corporate Trust Office of the Subordination Agent or any Loan Trustee
or the fiscal agent of the Policy Provider or the office of the Policy Provider
are located are authorized or obligated by law or executive order to close.

      "Deposit Agreement" means the Deposit Agreement dated as of the date
hereof between First Security Bank, National Association, as Escrow Agent and
ABN AMRO Bank N.V., acting through its Chicago branch, as Depositary, pertaining
to the Class C Certificates, as the same may be amended, modified or
supplemented from time to time in accordance with the terms thereof.

      "Depositary" has the meaning assigned to such term in the Deposit
Agreement.

      "Deposits" has the meaning assigned to such terms in the Deposit
Agreement.

      "Downgrade Advance" means an Advance made pursuant to Section 2.02(c).

      "Effective Date" has the meaning specified in Section 4.01. The delivery
of the certificate of the Liquidity Provider contemplated by Section 4.01(e)
shall be conclusive evidence that the Effective Date has occurred.
<PAGE>

      "Excluded Taxes" means (i) taxes imposed on the overall net income of the
Liquidity Provider or of its Facility Office by the jurisdiction where such
Liquidity Provider's principal office or such Facility Office is located, and
(ii) Excluded Withholding Taxes.

      "Excluded Withholding Taxes" means (i) withholding Taxes imposed by the
United States except (but only in the case of a successor Liquidity Provider
organized under the laws of a jurisdiction outside the United States) to the
extent that such United States withholding Taxes are imposed as a result of any
change in applicable law (excluding from change in applicable law for this
purpose a change in an applicable treaty or other change in law affecting the
applicability of a treaty) after the date hereof, or in the case of a successor
Liquidity Provider (including a transferee of an Advance) or Facility Office,
after the date on which such successor Liquidity Provider obtains its interest
or on which the Facility Office is changed, and (ii) any withholding Taxes
imposed by the United States which are imposed or increased as a result of the
Liquidity Provider failing to deliver to the Borrower any certificate or
document (which certificate or document in the good faith judgment of the
Liquidity Provider it is legally entitled to provide) which is reasonably
requested by the Borrower to establish that payments under this Agreement are
exempt from (or entitled to a reduced rate of) withholding Tax.

      "Expenses" means liabilities, obligations, damages, settlements,
penalties, claims, actions, suits, costs, expenses, and disbursements
(including, without limitation, reasonable fees and disbursements of legal
counsel and costs of investigation), provided that Expenses shall not include
any Taxes.

      "Expiry Date" means October 31, 2001, initially, or any date to which the
Expiry Date is extended pursuant to Section 2.10.

      "Facility Office" means the Facility Office of the Liquidity Provider
presently located at New York, New York, or such other Facility Office as the
Liquidity Provider from time to time shall notify the Borrower as its Facility
Office hereunder; provided that the Liquidity Provider shall not change its
Facility Office to another Facility Office outside the United States of America
except in accordance with Section 3.01, 3.02 or 3.03 hereof.

      "Final Advance" means an Advance made pursuant to Section 2.02(d).

      "Guarantor" has the meaning assigned to such term in the preliminary
statements of this Agreement.

      "Guarantee Agreement" has the meaning assigned to such term in the
preliminary statements of this Agreement.

      "Intercreditor Agreement" means the Intercreditor Agreement dated the date
hereof, among the Class C Trustee, the Class G Trustee, the Liquidity Provider,
the Policy Provider and the Subordination Agent, as the same may be amended,
supplemented or otherwise modified from time to time in accordance with its
terms.

      "Interest Advance" means an Advance made pursuant to Section 2.02(a).

      "Interest Period" means, with respect to any LIBOR Advance, each of the
following periods:

      (i)   the period beginning on the third Business Day following either (x)
            the Liquidity Provider's receipt of the Notice of Borrowing for such
            LIBOR

<PAGE>

            Advance or (y) the date of the withdrawal of funds from the Class C
            Cash Collateral Account for the purpose of paying interest on the
            Class C Certificates as contemplated by Section 2.06(a) hereof and,
            in either case, ending on the next Regular Distribution Date; and

      (ii)  each subsequent period commencing on the last day of the immediately
            preceding Interest Period and ending on the next Regular
            Distribution Date;

      provided, however, that if (x) the Final Advance shall have been made, or
      (y) other outstanding Advances shall have been converted into the Final
      Advance, then the Interest Periods shall be successive periods of one
      month beginning on the third Business Day following the Liquidity
      Provider's receipt of the Notice of Borrowing for such Final Advance (in
      the case of clause (x) above) or the Regular Distribution Date following
      such conversion (in the case of clause (y) above).

      "LIBOR Advance" means an Advance bearing interest at a rate based upon the
LIBOR Rate.

      "LIBOR Rate" means, with respect to any Interest Period:

      (i)   the rate per annum appearing on display page 3750 (British Bankers
            Association-LIBOR) of the Dow Jones Markets Service (or any
            successor or substitute therefor ) at approximately 11:00 a.m.
            (London time) two Business Days before the first day of such
            Interest Period, as the rate for dollar deposits with a maturity
            comparable to such Interest Period, or

      (ii)  if the rate calculated pursuant to clause (i) above is not
            available, the average (rounded upwards, if necessary, to the next
            1/16 of 1%) of the rates per annum at which deposits in dollars are
            offered for the relevant Interest Period by three banks of
            recognized standing selected by the Liquidity Provider in the London
            interbank market at approximately 11:00 a.m. (London time) two
            Business Days before the first day of such Interest Period in an
            amount approximately equal to the principal amount of the LIBOR
            Advance to which such Interest Period is to apply and for a period
            comparable to such Interest Period.

      "Liquidity Event of Default" means the occurrence of either (a) the
Acceleration of all of the Equipment Notes (provided that, with respect to the
period prior to the Delivery Period Expiry Date, such Equipment Notes have an
aggregate outstanding principal balance in excess of $250,000,000) or (b) a US
Airways Bankruptcy Event.

      "Liquidity Indemnitee" means (i) the Liquidity Provider, (ii) the
Guarantor, (iii) the respective directors, officers, employees and agents of the
Liquidity Provider and the Guarantor, and (iv) the successors and permitted
assigns of the persons described in clauses (i) through (iii), inclusive.
<PAGE>

      "Liquidity Provider" has the meaning assigned to such term in the recital
of parties to this Agreement.

      "Maximum Available Commitment" shall mean, subject to the proviso
contained in the third sentence of Section 2.02(a), at any time of
determination, (a) the Maximum Commitment at such time less (b) the aggregate
amount of each Interest Advance outstanding at such time; provided that
following a Provider Advance or a Final Advance, the Maximum Available
Commitment shall be zero.

      "Maximum Commitment" means initially $19,765,246, as the same may be
reduced or increased from time to time in accordance with Section 2.04(a).

      "Non-Excluded Tax" has the meaning specified in Section 3.03.

      "Non-Extension Advance" means an Advance made pursuant to Section 2.02(b).

      "Notice of Borrowing" has the meaning specified in Section 2.02(e).

      "Notice of Replacement Subordination Agent" has the meaning specified in
Section 3.08.

      "Performing Note Deficiency" means any time that less than 65% of the then
aggregate outstanding principal amount of all Equipment Notes are Performing
Equipment Notes.

      "Prospectus Supplement" means the Prospectus Supplement dated October 26,
2000 relating to the Certificates, as such Prospectus Supplement may be amended
or supplemented.

      "Provider Advance" means a Downgrade Advance or a Non-Extension Advance.

      "Reference Bank" has the meaning specified in Section 7.08(a).

      "Regulatory Change" has the meaning assigned to such term in Section 3.01.

      "Replenishment Amount" has the meaning assigned to such term in Section
2.06(b).

      "Required Amount" means, for any day, the sum of the aggregate amount of
interest, calculated at the rate per annum equal to the Stated Interest Rate for
the Class C Certificates, that would be payable on the Class C Certificates on
each of the three successive semiannual Regular Distribution Dates immediately
following such day or, if such day is a Regular Distribution Date, on such day
and the succeeding two semiannual Regular Distribution Dates, in each case
calculated on the basis of the Pool Balance of the Class C Certificates on such
day and without regard to expected future payments of principal on the Class C
Certificates. Notwithstanding the above, in the event of any Policy Provider
Election, for purposes of the definition of the Required Amount, the Pool
Balance shall be deemed to be reduced by the amount (if positive) by which (a)
the then outstanding principal balance of each Series G Equipment Note in
respect of which such Policy Provider Election has been made shall exceed (b)
the amount of any Policy Drawings previously paid by the Policy Provider in
respect of principal on such Series G Equipment Note.
<PAGE>

      "Termination Date" means the earliest to occur of the following: (i) the
Expiry Date; (ii) the date on which the Borrower delivers to the Liquidity
Provider a certificate, signed by a Responsible Officer of the Borrower,
certifying that all of the Class C Certificates have been paid in full (or
provision has been made for such payment in accordance with the Intercreditor
Agreement and the Class C Trust Agreement) or are otherwise no longer entitled
to the benefits of this Agreement; (iii) the date on which the Borrower delivers
to the Liquidity Provider a certificate, signed by a Responsible Officer of the
Borrower, certifying that a Replacement Liquidity Facility has been substituted
for this Agreement in full pursuant to Section 3.6(e) of the Intercreditor
Agreement; (iv) the fifth Business Day following the receipt by the Borrower of
a Termination Notice from the Liquidity Provider pursuant to Section 6.01
hereof; and (v) the date on which no Advance is, or may (including by reason of
reinstatement as herein provided) become, available for a Borrowing hereunder.

      "Termination Notice" means the Notice of Termination substantially in the
form of Annex V to this Agreement.

      "Transferee" has the meaning assigned to such term in Section 7.08(b).

      "Unapplied Downgrade Advance" means any Downgrade Advance other than an
Applied Downgrade Advance.

      "Unapplied Non-Extension Advance" means any Non-Extension Advance other
than an Applied Non-Extension Advance.

      "Unapplied Provider Advance" means any Provider Advance other than an
Applied Provider Advance.

      "Unpaid Advance" has the meaning assigned to such term in Section 2.05.

      (b) Terms Defined in the Intercreditor Agreement. For all purposes of this
Agreement, the following terms shall have the respective meanings assigned to
such terms in the Intercreditor Agreement:

      "Acceleration", "Certificates", "Class G Certificates", "Class C Cash
Collateral Account", "Class C Certificateholders", "Class C Certificates",
"Class C Trust", "Class C Trust Agreement", "Class C Trustee", "Closing Date",
"Controlling Party", "Corporate Trust Office", "Delivery Period Expiry Date",
"Distribution Date", "Downgraded Facility", "Equipment Notes", "Final Legal
Distribution Date", "Financing Agreement", "Indenture", "Interest Payment Date",
"Investment Earnings", "Leased Aircraft", "Liquidity Facility", "Liquidity
Facility Fee Letter", "Liquidity Obligations", "Loan Trustee", "Moody's",
"Non-Extended Facility", "Note Purchase Agreement", "Operative Agreements",
"Owned Aircraft", "Participation Agreement", "Performing Equipment Note",
"Person", "Policy Drawings", "Policy Provider", "Policy Provider Election",
"Pool Balance", "Rating Agency", "Ratings Confirmation", "Regular Distribution
Date", "Replacement Liquidity Facility", "Responsible Officer", "Scheduled
Payment", "Series G Equipment Note", "Special Payment", "Standard & Poor's",
"Stated Interest Rate", "Subordination Agent", "Taxes", "Threshold Rating",
"Trustee", "Underwriters", "Underwriting Agreement", "US Airways", "US Airways
Bankruptcy Event" and "Written Notice".
<PAGE>

                                   ARTICLE II

                       AMOUNT AND TERMS OF THE COMMITMENT

      Section 2.01. The Advances. The Liquidity Provider hereby irrevocably
agrees, on the terms and conditions hereinafter set forth, to make Advances to
the Borrower from time to time on any Business Day during the period from the
Effective Date until 1:00 p.m. (New York City time) on the Expiry Date (unless
the obligations of the Liquidity Provider shall be earlier terminated in
accordance with the terms of Section 2.04(b)) in an aggregate amount at any time
outstanding not to exceed the Maximum Commitment.

      Section 2.02. Making the Advances. (a) Interest Advances shall be made in
one or more Borrowings by delivery to the Liquidity Provider of one or more
written and completed Notices of Borrowing in substantially the form of Annex I
attached hereto, signed by a Responsible Officer of the Borrower, in an amount
not exceeding the Maximum Available Commitment at such time and shall be used
solely for the payment when due of interest on the Class C Certificates at the
Stated Interest Rate therefor in accordance with Section 3.6(a) of the
Intercreditor Agreement. Each Interest Advance made hereunder shall
automatically reduce the Maximum Available Commitment and the amount available
to be borrowed hereunder by subsequent Advances by the amount of such Interest
Advance (subject to reinstatement as provided in the next sentence). Upon
repayment to the Liquidity Provider of all or any part of the amount of any
Interest Advance made pursuant to this Section 2.02(a), together with accrued
interest thereon (as provided herein), the Maximum Available Commitment shall be
reinstated by the amount of such repaid Interest Advance, but not to exceed the
Maximum Commitment; provided, however, that the Maximum Available Commitment
shall not be so reinstated at any time if (i) a Liquidity Event of Default shall
have occurred and be continuing and (ii) there is a Performing Note Deficiency.

      (b) A Non-Extension Advance shall be made in a single Borrowing if this
Agreement is not extended in accordance with Section 3.6(d) of the Intercreditor
Agreement (unless a Replacement Liquidity Facility to replace this Agreement
shall have been delivered to the Borrower as contemplated by said Section 3.6(d)
within the time period specified in such Section) by delivery to the Liquidity
Provider of a written and completed Notice of Borrowing in substantially the
form of Annex II attached hereto, signed by a Responsible Officer of the
Borrower, in an amount equal to the Maximum Available Commitment at such time,
and shall be used to fund the Class C Cash Collateral Account in accordance with
said Section 3.6(d) and Section 3.6(f) of the Intercreditor Agreement.

      (c) A Downgrade Advance shall be made in a single Borrowing upon a
downgrading of the Guarantor's short-term unsecured debt rating issued by either
Rating Agency below the applicable Threshold Rating or the Guarantee Agreement
ceasing to be in full force and effect or becoming invalid or unenforceable or
the Guarantor denying its liability thereunder (as provided for in Section
3.6(c) of the Intercreditor Agreement) unless a Replacement Liquidity Facility
to replace this Agreement shall have been previously delivered to the Borrower
in accordance with said Section 3.6(c) and within the time period specified in
such Section, by delivery to the Liquidity Provider of a written and completed
Notice of Borrowing in substantially the form of Annex III attached hereto,
signed by a Responsible Officer of the Borrower, in an amount equal to the
Maximum Available Commitment at such time, and shall be used to fund the Class C
Cash Collateral Account in accordance with said Section 3.6(c) and Section
3.6(f) of the Intercreditor Agreement.

      (d) A Final Advance shall be made in a single Borrowing upon the receipt
by the Borrower of a Termination Notice from the Liquidity Provider pursuant to
Section 6.01 hereof by delivery to the Liquidity Provider of a written and
completed Notice of Borrowing in substantially the form of Annex IV attached
hereto, signed by a Responsible Officer of the Borrower, in an amount equal to
the Maximum Available Commitment at such time, and shall be used to fund the
Class C Cash Collateral Account in accordance with Section 3.6(i) and Section
3.6(f) of the Intercreditor Agreement.
<PAGE>

      (e) Each Borrowing shall be made on notice in writing (a "Notice of
Borrowing") in substantially the form required by Section 2.02(a), 2.02(b),
2.02(c) or 2.02(d), as the case may be, given by the Borrower to the Liquidity
Provider. If a Notice of Borrowing is delivered by the Borrower in respect of
any Borrowing no later than 1:00 p.m. (New York City time) on a Business Day,
upon satisfaction of the conditions precedent set forth in Section 4.02 with
respect to a requested Borrowing, the Liquidity Provider shall make available to
the Borrower, in accordance with its payment instructions, the amount of such
Borrowing in U.S. dollars and immediately available funds, before 4:00 p.m. (New
York City time) on such Business Day or on such later Business Day specified in
such Notice of Borrowing. If a Notice of Borrowing is delivered by the Borrower
in respect of any Borrowing after 1:00 p.m. (New York City time) on a Business
Day, upon satisfaction of the conditions precedent set forth in Section 4.02
with respect to a requested Borrowing, the Liquidity Provider shall make
available to the Borrower, in accordance with its payment instructions, the
amount of such Borrowing in U.S. dollars and in immediately available funds,
before 12:00 noon (New York City time) on the first Business Day next following
the day of receipt of such Notice of Borrowing or on such later Business Day
specified by the Borrower in such Notice of Borrowing. Payments of proceeds of a
Borrowing shall be made by wire transfer of immediately available funds to the
Borrower in accordance with such wire transfer instructions as the Borrower
shall furnish from time to time to the Liquidity Provider for such purpose. Each
Notice of Borrowing shall be irrevocable and binding on the Borrower.

      (f) Upon the making of any Advance requested pursuant to a Notice of
Borrowing, in accordance with the Borrower's payment instructions, the Liquidity
Provider shall be fully discharged of its obligation hereunder with respect to
such Notice of Borrowing, and the Liquidity Provider shall not thereafter be
obligated to make any further Advances hereunder in respect of such Notice of
Borrowing to the Borrower or to any other Person. If the Liquidity Provider
makes an Advance requested pursuant to a Notice of Borrowing before 12:00 noon
(New York City time) on the second Business Day after the date of payment
specified in said Section 2.02(e), the Liquidity Provider shall have fully
discharged its obligations hereunder with respect to such Advance and an event
of default shall not have occurred hereunder. Following the making of any
Advance pursuant to Section 2.02(b), (c) or (d) hereof to fund the Class C Cash
Collateral Account, the Liquidity Provider shall have no interest in or rights
to the Class C Cash Collateral Account, such Advance or any other amounts from
time to time on deposit in the Class C Cash Collateral Account; provided that
the foregoing shall not affect or impair the obligations of the Subordination
Agent to make the distributions contemplated by Section 3.6(e) or (f) of the
Intercreditor Agreement. By paying to the Borrower proceeds of Advances
requested by the Borrower in accordance with the provisions of this Agreement,
the Liquidity Provider makes no representation as to, and assumes no
responsibility for, the correctness or sufficiency for any purpose of the amount
of the Advances so made and requested.

      Section 2.03. Fees. The Borrower agrees to pay to the Liquidity Provider
the fees set forth in the Liquidity Facility Fee Letter applicable to this
Agreement.
<PAGE>

      Section 2.04. Reductions, Increases or Termination of the Maximum
Commitment.

      (a) Automatic Reduction or Increase. Promptly following each date on which
the Required Amount is (1) reduced as a result of a reduction in the Pool
Balance of the Class C Certificates or otherwise, (2) increased as a result of
an increase in the Stated Interest Rate or (3) subsequent to such an increase
described in clause (2), reduced pursuant to the definition of "Stated Interest
Rate," the Maximum Commitment shall automatically be reduced or increased to an
amount equal to such reduced or increased Required Amount (as calculated by the
Borrower). The Borrower shall give notice of any such automatic reduction or
increase of the Maximum Commitment to the Liquidity Provider within two Business
Days thereof. The failure by the Borrower to furnish any such notice shall not
affect such automatic reduction or increase of the Maximum Commitment.

      (b) Termination. Upon the making of any Provider Advance or Final Advance
hereunder or the occurrence of the Termination Date, the obligation of the
Liquidity Provider to make further Advances hereunder shall automatically and
irrevocably terminate, and the Borrower shall not be entitled to request any
further Borrowing hereunder.

      Section 2.05. Repayments of Interest Advances or the Final Advance.
Subject to Sections 2.06, 2.07 and 2.09 hereof, the Borrower hereby agrees,
without notice of an Advance or demand for repayment from the Liquidity Provider
(which notice and demand are hereby waived by the Borrower), to pay, or to cause
to be paid, to the Liquidity Provider on each date on which the Liquidity
Provider shall make an Interest Advance or the Final Advance, an amount equal to
(a) the amount of such Advance (any such Advance, until repaid, is referred to
herein as an "Unpaid Advance"), plus (b) interest on the amount of each such
Unpaid Advance as provided in Section 3.07 hereof; provided that if (i) the
Liquidity Provider shall make a Provider Advance at any time after making one or
more Interest Advances which shall not have been repaid in accordance with this
Section 2.05 or (ii) this Liquidity Facility shall become a Downgraded Facility
or Non-Extended Facility at any time when unreimbursed Interest Advances have
reduced the Maximum Available Commitment to zero, then such Interest Advances
shall cease to constitute Unpaid Advances and shall be deemed to have been
changed into an Applied Downgrade Advance or an Applied Non-Extension Advance,
as the case may be, for all purposes of this Agreement (including, without
limitation, for the purpose of determining when such Interest Advance is
required to be repaid to the Liquidity Provider in accordance with Section 2.06
and for the purposes of Section 2.06(b)). The Borrower and the Liquidity
Provider agree that the repayment in full of each Interest Advance and Final
Advance on the date such Advance is made is intended to be a contemporaneous
exchange for new value given to the Borrower by the Liquidity Provider.

      Section 2.06. Repayments of Provider Advances. (a) Amounts advanced
hereunder in respect of a Provider Advance shall be deposited in the Class C
Cash Collateral Account, invested and withdrawn from the Class C Cash Collateral
Account as set forth in Sections 3.6(c), (d) and (f) of the Intercreditor
Agreement. The Borrower agrees to pay to the Liquidity Provider, on each Regular
Distribution Date, commencing on the first Regular Distribution Date after the
making of a Provider Advance, interest on the principal amount of any such
Provider Advance as provided in Section 3.07 hereof; provided, however, that
amounts in respect of a Provider Advance withdrawn from the Class C Cash
Collateral Account for the purpose of paying interest on the Class C
Certificates in accordance with Section 3.6(f) of the Intercreditor Agreement
(the amount of any such withdrawal being (y) in the case of a Downgrade Advance,
an "Applied Downgrade Advance" and (z) in the case of a Non-Extension Advance,
an "Applied Non-Extension Advance" and, together with an Applied Downgrade
Advance, an "Applied Provider Advance") shall thereafter (subject to Section
2.06(b)) be treated as an Interest Advance under this Agreement for purposes of
determining the Applicable Liquidity Rate for interest payable
<PAGE>

thereon; provided further, however, that if, following the making of a Provider
Advance, the Liquidity Provider delivers a Termination Notice to the Borrower
pursuant to Section 6.01 hereof, such Provider Advance shall thereafter be
treated as a Final Advance under this Agreement for purposes of determining the
Applicable Liquidity Rate for interest payable thereon. Subject to Sections 2.07
and 2.09 hereof, immediately upon the withdrawal of any amounts from the Class C
Cash Collateral Account on account of a reduction in the Required Amount, the
Borrower shall repay to the Liquidity Provider a portion of the Provider
Advances in a principal amount equal to such reduction, plus interest on the
principal amount prepaid as provided in Section 3.07 hereof.

      (b) At any time when an Applied Provider Advance (or any portion thereof)
is outstanding, upon the deposit in the Class C Cash Collateral Account of any
amount pursuant to clause "third" of Section 2.4(b) of the Intercreditor
Agreement, clause "third" of Section 3.2 of the Intercreditor Agreement or
clause "fourth" of Section 3.3 of the Intercreditor Agreement (any such amount
being a "Replenishment Amount") for the purpose of replenishing or increasing
the balance thereof up to the Required Amount at such time, (i) the aggregate
outstanding principal amount of all Applied Provider Advances (and of Provider
Advances treated as an Interest Advance for purposes of determining the
Applicable Liquidity Rate for interest payable thereon) shall be automatically
reduced by the amount of such Replenishment Amount and (ii) the aggregate
outstanding principal amount of all Unapplied Provider Advances shall be
automatically increased by the amount of such Replenishment Amount.

      (c) Upon the provision of a Replacement Liquidity Facility in replacement
of this Agreement in accordance with Section 3.6(e) of the Intercreditor
Agreement, amounts remaining on deposit in the Class C Cash Collateral Account
after giving effect to any Applied Provider Advance on the date of such
replacement shall be reimbursed to the Liquidity Provider, but only to the
extent such amounts are necessary to repay in full to the Liquidity Provider all
amounts owing to it hereunder.

      Section 2.07. Payments to the Liquidity Provider Under the Intercreditor
Agreement. In order to provide for payment or repayment to the Liquidity
Provider of any amounts hereunder, the Intercreditor Agreement provides that
amounts available and referred to in Articles II and III of the Intercreditor
Agreement, to the extent payable to the Liquidity Provider pursuant to the terms
of the Intercreditor Agreement (including, without limitation, Section 3.6(f) of
the Intercreditor Agreement), shall be paid to the Liquidity Provider in
accordance with the terms thereof. Amounts so paid to the Liquidity Provider
shall be applied by the Liquidity Provider to Liquidity Obligations then due and
payable in accordance with the Intercreditor Agreement or, if not provided for
in the Intercreditor Agreement, then in such manner as the Liquidity Provider
shall deem appropriate.

      Section 2.08. Book Entries. The Liquidity Provider shall maintain in
accordance with its usual practice an account or accounts evidencing the
indebtedness of the Borrower resulting from Advances made from time to time and
the amounts of principal and interest payable hereunder and paid from time to
time in respect thereof; provided, however, that the failure by the Liquidity
Provider to maintain such account or accounts shall not affect the obligations
of the Borrower in respect of Advances.

      Section 2.09. Payments from Available Funds Only. All payments to be made
by the Borrower under this Agreement shall be made only from the amounts that
constitute Scheduled Payments, Special Payments or payments under Section 6(c)
or 6(b), as the case may be, of the Participation Agreements and Section 7 of
the Note Purchase Agreement and
<PAGE>

only to the extent that the Borrower shall have sufficient income or proceeds
therefrom to enable the Borrower to make payments in accordance with the terms
hereof after giving effect to the priority of payments provisions set forth in
the Intercreditor Agreement. The Liquidity Provider agrees that it will look
solely to such amounts to the extent available for distribution to it as
provided in the Intercreditor Agreement and this Agreement and that the
Borrower, in its individual capacity, is not personally liable to it for any
amounts payable or liability under this Agreement except as expressly provided
in this Agreement, the Intercreditor Agreement or any Participation Agreement.
Amounts on deposit in the Class C Cash Collateral Account shall be available to
the Borrower to make payments under this Agreement only to the extent and for
the purposes expressly contemplated in Section 3.6(f) of the Intercreditor
Agreement.

      Section 2.10. Extension of the Expiry Date; Non-Extension Advance. The
Expiry Date shall be automatically extended, effective on the 25th day prior to
each Expiry Date, for a period of 364 days after such Expiry Date (unless the
obligations of the Liquidity Provider are earlier terminated in accordance with
the terms hereof), without the necessity of any act on the part of the Borrower
or the Liquidity Provider, unless the Liquidity Provider shall advise the
Borrower prior to such 25th day that it does not agree to such extension of such
Expiry Date, in which event (and if the Liquidity Provider shall not have been
replaced in accordance with Section 3.6(e) of the Intercreditor Agreement), the
Borrower shall be entitled on and after such 25th day (but prior to such Expiry
Date) to request a Non-Extension Advance in accordance with Section 2.02(b)
hereof and Section 3.6(d) of the Intercreditor Agreement.

                                   ARTICLE III

                           OBLIGATIONS OF THE BORROWER

      Section 3.01. Increased Costs. The Borrower shall pay to the Liquidity
Provider from time to time such amounts as may be necessary to compensate the
Liquidity Provider for any increased costs incurred by the Liquidity Provider
which are attributable to its making or maintaining any LIBOR Advances hereunder
or its obligation to make any such Advances hereunder, or any reduction in any
amount receivable by the Liquidity Provider under this Agreement or the
Intercreditor Agreement in respect of any such Advances or such obligation (such
increases in costs and reductions in amounts receivable being herein called
"Additional Costs"), resulting from any change after the date of this Agreement
in U.S. federal, state, municipal, or foreign laws or regulations (including
Regulation D of the Board of Governors of the Federal Reserve System), or the
adoption or making after the date of this Agreement of any interpretations,
directives, or requirements applying to a class of banks including the Liquidity
Provider under any U.S. federal, state, municipal, or any foreign laws or
regulations (whether or not having the force of law) by any court, central bank
or monetary authority charged with the interpretation or administration thereof
(a "Regulatory Change"), which: (1) changes the basis of taxation of any amounts
payable to the Liquidity Provider under this Agreement in respect of any such
Advances (other than Excluded Taxes); or (2) imposes or modifies any reserve,
special deposit, compulsory loan or similar requirements relating to any
extensions of credit or other assets of, or any deposits with other liabilities
of, the Liquidity Provider (including any such Advances or any deposits referred
to in the definition of LIBOR Rate or related definitions). The Liquidity
Provider agrees to use reasonable efforts (consistent with applicable legal and
regulatory restrictions) to change the jurisdiction of its Facility Office if
making such change would avoid the need for, or reduce the amount of, any amount
payable under this Section that may thereafter accrue and would not, in the
reasonable judgment of the Liquidity Provider, be otherwise disadvantageous to
the Liquidity Provider.
<PAGE>

      The Liquidity Provider will notify the Borrower of any event occurring
after the date of this Agreement that will entitle the Liquidity Provider to
compensation pursuant to this Section 3.01 as promptly as practicable after it
obtains knowledge thereof and determines to request such compensation, which
notice shall describe in reasonable detail the calculation of the amounts owed
under this Section. Determinations by the Liquidity Provider for purposes of
this Section 3.01 of the effect of any Regulatory Change on its costs of making
or maintaining Advances or on amounts receivable by it in respect of Advances,
and of the additional amounts required to compensate the Liquidity Provider in
respect of any Additional Costs, shall be prima facie evidence of the amount
owed under this Section.

      Notwithstanding the preceding two paragraphs, the Liquidity Provider and
the Subordination Agent agree that the initial Liquidity Provider (i.e., Morgan
Stanley Capital Services Inc.) shall not be entitled to the benefits of the
preceding two paragraphs; provided, however, any permitted assignee or
participant of the initial Liquidity Provider which is a bank organized under
the laws of the United States or any State thereof shall be entitled to the
benefits of the preceding two paragraphs (subject, in the case of any permitted
participant, to the limitations set forth in Section 7.08 hereof).

      Section 3.02. Capital Adequacy. If (1) the adoption, after the date
hereof, of any applicable governmental law, rule or regulation regarding capital
adequacy, (2) any change, after the date hereof, in the interpretation or
administration of any such law, rule or regulation by any central bank or other
governmental authority charged with the interpretation or administration thereof
or (3) compliance by the Liquidity Provider or any corporation controlling the
Liquidity Provider with any applicable guideline or request of general
applicability, issued after the date hereof, by any central bank or other
governmental authority (whether or not having the force of law) that constitutes
a change of the nature described in clause (2), has the effect of requiring an
increase in the amount of capital required to be maintained by the Liquidity
Provider or any corporation controlling the Liquidity Provider, and such
increase is based upon the Liquidity Provider's obligations hereunder and other
similar obligations, the Borrower shall pay to the Liquidity Provider from time
to time such additional amount or amounts as are necessary to compensate the
Liquidity Provider for such portion of such increase as shall be reasonably
allocable to the Liquidity Provider's obligations to the Borrower hereunder. The
Liquidity Provider agrees to use reasonable efforts (consistent with applicable
legal and regulatory restrictions) to change the jurisdiction of its Facility
Office if making such change would avoid the need for, or reduce the amount of,
any amount payable under this Section that may thereafter accrue and would not,
in the reasonable judgment of the Liquidity Provider, be otherwise materially
disadvantageous to the Liquidity Provider.

      The Liquidity Provider will notify the Borrower of any event occurring
after the date of this Agreement that will entitle the Liquidity Provider to
compensation pursuant to this Section 3.02 as promptly as practicable after it
obtains knowledge thereof and determines to request such compensation, which
notice shall describe in reasonable detail the calculation of the amounts owed
under this Section. Determinations by the Liquidity Provider for purposes of
this Section 3.02 of the effect of any increase in the amount of capital
required to be maintained by the Liquidity Provider and of the amount allocable
to the Liquidity Provider's obligations to the Borrower hereunder shall be prima
facie evidence of the amounts owed under this Section.
<PAGE>

      Notwithstanding the preceding two paragraphs, the Liquidity Provider and
the Subordination Agent agree that the initial Liquidity Provider (i.e., Morgan
Stanley Capital Services Inc.) shall not be entitled to the benefits of the
preceding two paragraphs; provided, however, any permitted assignee or
participant of the initial Liquidity Provider which is a bank organized under
the laws of the United States or any State thereof shall be entitled to the
benefits of the preceding two paragraphs (subject, in the case of any permitted
participant, to the limitations set forth in Section 7.08 hereof).

      Section 3.03. Payments Free of Deductions. (a) All payments made by the
Borrower under this Agreement shall be made free and clear of, and without
reduction for or on account of, any present or future stamp or other taxes,
levies, imposts, duties, charges, fees, deductions, withholdings, restrictions
or conditions of any nature whatsoever now or hereafter imposed, levied,
collected, withheld or assessed, excluding Excluded Taxes (such non-excluded
taxes being referred to herein, collectively, as "Non-Excluded Taxes" and,
individually, as a "Non-Excluded Tax"). If any Non-Excluded Taxes are required
to be withheld from any amounts payable to the Liquidity Provider under this
Agreement, the amounts so payable to the Liquidity Provider shall be increased
to the extent necessary to yield to the Liquidity Provider (after payment of all
Non-Excluded Taxes) interest or any other such amounts payable under this
Agreement at the rates or in the amounts specified in this Agreement. The
Liquidity Provider agrees to use reasonable efforts (consistent with its
internal policy and legal and regulatory restrictions) to change the
jurisdiction of its Facility Office if making such change would avoid the need
for, or reduce the amount of, any such additional amounts that may thereafter
accrue and would not, in the reasonable judgment of the Liquidity Provider, be
otherwise disadvantageous to the Liquidity Provider. From time to time upon the
reasonable request of the Borrower, if the Liquidity Provider is not organized
under the laws of the United States or any State thereof, the Liquidity Provider
agrees to provide to the Borrower two original Internal Revenue Service Form
W-8BEN or W-8ECI, as appropriate, or any successor or other form prescribed by
the Internal Revenue Service, certifying that the Liquidity Provider is exempt
from or entitled to a reduced rate of United States withholding tax on payments
pursuant to this Agreement.

      (b) All payments (including, without limitation, Advances) made by the
Liquidity Provider under this Agreement shall be made free and clear of, and
without reduction for or on account of, any Taxes. If any Taxes are required to
be withheld or deducted from any amounts payable to the Borrower under this
Agreement, the Liquidity Provider shall (i) within the time prescribed therefor
by applicable law pay to the appropriate governmental or taxing authority the
full amount of any such Taxes (and any additional Taxes in respect of the
additional amounts payable under clause (ii) hereof) and make such reports or
returns in connection therewith at the time or times and in the manner
prescribed by applicable law, and (ii) pay to the Borrower an additional amount
which (after deduction of all such Taxes) will be sufficient to yield to the
Borrower the full amount which would have been received by it had no such
withholding or deduction been made. Within 30 days after the date of each
payment hereunder, the Liquidity Provider shall furnish to the Borrower the
original or a certified copy of (or other documentary evidence of) the payment
of the Taxes applicable to such payment.

      (c) If any exemption from, or reduction in the rate of, any Taxes is
reasonably available to the Borrower to establish that payments under this
Agreement are exempt from (or entitled to a reduced rate of) Tax, the Borrower
shall deliver to the Liquidity Provider such form or forms and such other
evidence of the eligibility of the Borrower
<PAGE>

for such exemption or reduction as the Liquidity Provider may reasonably
identify to the Borrower as being required as a condition to exemption from, or
reduction in the rate of, any Taxes.

      Section 3.04. Payments. The Borrower shall make or cause to be made each
payment to the Liquidity Provider under this Agreement so as to cause the same
to be received by the Liquidity Provider not later than 1:00 p.m. (New York City
time) on the day when due. The Borrower shall make all such payments in lawful
money of the United States of America, to the Liquidity Provider in immediately
available funds, by wire transfer to Citibank, N.A., New York, NY, ABA#
021000089, Account Name: Morgan Stanley Capital Services Inc., in favor of
account number 4072-4601, Reference: US Airways, Inc. EETC 2000-3.

      Section 3.05. Computations. All computations of interest based on the Base
Rate shall be made on the basis of a year of 365 or 366 days, as the case may
be, and all computations of interest based on the LIBOR Rate shall be made on
the basis of a year of 360 days, in each case for the actual number of days
(including the first day but excluding the last day) occurring in the period for
which such interest is payable.

      Section 3.06. Payment on Non-Business Days. Whenever any payment to be
made hereunder shall be stated to be due on a day other than a Business Day,
such payment shall be made on the next succeeding Business Day and no additional
interest shall be due as a result (and if so made, shall be deemed to have been
made when due). If any payment in respect of interest on an Advance is so
deferred to the next succeeding Business Day, such deferral shall not delay the
commencement of the next Interest Period for such Advance (if such Advance is a
LIBOR Advance) or reduce the number of days for which interest will be payable
on such Advance on the next interest payment date for such Advance.

      Section 3.07. Interest. (a) Subject to Section 2.09, the Borrower shall
pay, or shall cause to be paid, without duplication, interest on (i) the unpaid
principal amount of each Advance from and including the date of such Advance
(or, in the case of an Applied Provider Advance, from and including the date on
which the amount thereof was withdrawn from the Class C Cash Collateral Account
to pay interest on the Class C Certificates) to but excluding the date such
principal amount shall be paid in full (or, in the case of an Applied Provider
Advance, the date on which the Class C Cash Collateral Account is fully
replenished in respect of such Advance) and (ii) any other amount due hereunder
(whether fees, commissions, expenses or other amounts or, to the extent
permitted by law, installments of interest on Advances or any such other amount)
which is not paid when due (whether at stated maturity, by acceleration or
otherwise) from and including the due date thereof to but excluding the date
such amount is paid in full, in each such case, at a fluctuating interest rate
per annum for each day equal to the Applicable Liquidity Rate (as defined below)
for such Advance or such other amount as in effect for such day, but in no event
at a rate per annum greater than the maximum rate permitted by applicable law;
provided, however, that, if at any time the otherwise applicable interest rate
as set forth in this Section 3.07 shall exceed the maximum rate permitted by
applicable law, then any subsequent reduction in such interest rate will not
reduce the rate of interest payable pursuant to this Section 3.07 below the
maximum rate permitted by applicable law until the total amount of interest
accrued equals the amount of interest that would have accrued if such otherwise
applicable interest rate as set forth in this Section 3.07 had at all times been
in effect.

      (b) Each Advance will be either a Base Rate Advance or a LIBOR Advance as
provided in this Section. Each such Advance will be a Base Rate Advance for the
period from the date of its borrowing to (but excluding) the third Business Day
following the Liquidity Provider's
<PAGE>

receipt of the Notice of Borrowing for such Advance. Thereafter, such Advance
shall be a LIBOR Advance; provided that the Borrower (at the direction of the
Controlling Party, so long as the Liquidity Provider is not the Controlling
Party) may (x) convert the Final Advance into a Base Rate Advance on the last
day of an Interest Period for such Advance by giving the Liquidity Provider no
less than four Business Days' prior written notice of such election or (y) elect
to maintain the Final Advance as a Base Rate Advance by not requesting a
conversion of the Final Advance to a LIBOR Advance under Clause (5) of the
applicable Notice of Borrowing (or, if such Final Advance is deemed to have been
made, without delivery of a Notice of Borrowing pursuant to Section 2.06, by
requesting, prior to 11:00 a.m. on the first Business Day immediately following
the Borrower's receipt of the applicable Termination Notice, that such Final
Advance not be converted from a Base Rate Advance to a LIBOR Advance).

      (c) Each LIBOR Advance shall bear interest during each Interest Period at
a rate per annum equal to the LIBOR Rate for such Interest Period plus the
Applicable Margin for such LIBOR Advance, payable in arrears on the last day of
such Interest Period and, in the event of the payment of principal of such LIBOR
Advance on a day other than such last day, on the date of such payment (to the
extent of interest accrued on the amount of principal repaid).

      (d) Each Base Rate Advance shall bear interest at a rate per annum equal
to the Base Rate plus the Applicable Margin for such Base Rate Advance, payable
in arrears on each Regular Distribution Date and, in the event of the payment of
principal of such Base Rate Advance on a day other than a Regular Distribution
Date, on the date of such payment (to the extent of interest accrued on the
amount of principal repaid).

      (e) Each amount not paid when due hereunder (whether fees, commissions,
expenses or other amounts or, to the extent permitted by applicable law,
installments of interest on Advances but excluding Advances) shall bear interest
at a rate per annum equal to the Base Rate plus 2.00% until paid.

      (f) Each change in the Base Rate shall become effective immediately. The
rates of interest specified in this Section 3.07 with respect to any Advance or
other amount shall be referred to as the "Applicable Liquidity Rate".

      Section 3.08. Replacement of Borrower. From time to time and subject to
the successor Borrower's meeting the eligibility requirements set forth in
Section 6.9 of the Intercreditor Agreement applicable to the Subordination
Agent, upon the effective date and time specified in a written and completed
Notice of Replacement Subordination Agent in substantially the form of Annex VI
attached hereto (a "Notice of Replacement Subordination Agent") delivered to the
Liquidity Provider by the then Borrower, the successor Borrower designated
therein shall be substituted for as the Borrower for all purposes hereunder.

      Section 3.09. Funding Loss Indemnification. The Borrower shall pay to the
Liquidity Provider, upon the request of the Liquidity Provider, such amount or
amounts as shall be sufficient (in the reasonable opinion of the Liquidity
Provider) to compensate it for any loss, cost, or expense incurred by reason of
the liquidation or redeployment of deposits or other funds acquired by the
Liquidity Provider to fund or maintain any LIBOR Advance (but excluding loss of
anticipated profits) incurred as a result of:
<PAGE>

      (1) Any repayment of a LIBOR Advance on a date other than the last day of
the Interest Period for such Advance; or

      (2) Any failure by the Borrower to borrow a LIBOR Advance on the date for
borrowing specified in the relevant notice under Section 2.02.

      Section 3.10. Illegality. Notwithstanding any other provision in this
Agreement, if any change in any applicable law, rule or regulation, or any
change in the interpretation or administration thereof by any governmental
authority, central bank or comparable agency charged with the interpretation or
administration thereof, or compliance by the Liquidity Provider (or its Facility
Office) with any request or directive (whether or not having the force of law)
of any such authority, central bank or comparable agency shall make it unlawful
or impossible for the Liquidity Provider (or its Facility Office) to maintain or
fund its LIBOR Advances, then upon notice to the Borrower by the Liquidity
Provider, the outstanding principal amount of the LIBOR Advances shall be
converted to Base Rate Advances (a) immediately upon demand of the Liquidity
Provider, if such change or compliance with such request, in the judgment of the
Liquidity Provider, requires immediate repayment; or (b) at the expiration of
the last Interest Period to expire before the effective date of any such change
or request.

                                   ARTICLE IV

                              CONDITIONS PRECEDENT

      Section 4.01. Conditions Precedent to Effectiveness of Section 2.01.
Section 2.01 of this Agreement shall become effective on and as of the first
date (the "Effective Date") on which the following conditions precedent have
been satisfied or waived:

      (a) The Liquidity Provider shall have received on or before the Closing
Date each of the following, and in the case of each document delivered pursuant
to paragraphs (i), (ii) and (iii), each in form and substance satisfactory to
the Liquidity Provider:

      (i)   This Agreement duly executed on behalf of the Borrower;

      (ii)  The Intercreditor Agreement duly executed on behalf of each of the
            parties thereto;

      (iii) Fully executed copies of each of the Operative Agreements executed
            and delivered on or before the Closing Date (other than this
            Agreement and the Intercreditor Agreement);

      (iv)  A copy of the Prospectus Supplement and specimen copies of the Class
            C Certificates;

      (v)   An executed copy of each document, instrument, certificate and
            opinion delivered on or before the Closing Date pursuant to the
            Class C Trust Agreement, the Intercreditor Agreement and the other
            Operative Agreements (in the case of each such opinion, other than
            the opinion of counsel for the Underwriters, either addressed to the
            Liquidity Provider or accompanied by a letter from the counsel
            rendering such opinion to the effect that the Liquidity Provider is
            entitled to rely on such opinion as of its date as if it were
            addressed to the Liquidity Provider);
<PAGE>

      (vi)   Evidence that there shall have been made and shall be in full force
             and effect, all filings, recordings and/or registrations, and there
             shall have been given or taken any notice or other similar action
             as may be reasonably necessary or, to the extent reasonably
             requested by the Liquidity Provider, reasonably advisable, in order
             to establish, perfect, protect and preserve the right, title and
             interest, remedies, powers, privileges, liens and security
             interests of, or for the benefit of, the Class C Trustee, the
             Borrower and the Liquidity Provider created by the Operative
             Agreements executed and delivered on or prior to the Closing Date;

      (vii)  An agreement from US Airways, pursuant to which (i) US Airways
             agrees to provide copies of quarterly financial statements and
             audited annual financial statements to the Liquidity Provider, and
             such other information as the Liquidity Provider shall reasonably
             request with respect to the transactions contemplated by the
             Operative Agreements, in each case, only to the extent that US
             Airways is obligated to provide such information pursuant to
             Section 16 of the Basic Lease or Section 7 of the Special Leased
             Aircraft Participation Agreement (related to Leased Aircraft) to
             the extent such provisions require delivery of financial
             statements, or the corresponding section of the Indentures (related
             to Owned Aircraft) to the parties thereto and (ii) US Airways
             agrees to allow the Liquidity Provider to inspect US Airways' books
             and records regarding such transactions, and to discuss such
             transactions with officers and employees of US Airways; and

      (viii) Such other documents, instruments, opinions and approvals
             pertaining to the transactions contemplated hereby or by the other
             Operative Agreements as the Liquidity Provider shall have
             reasonably requested.

      (b) The following statement shall be true on and as of the Effective Date:
no event has occurred and is continuing, or would result from the entering into
of this Agreement or the making of any Advance, which constitutes a Liquidity
Event of Default.

      (c) The Liquidity Provider shall have received payment in full of all fees
and other sums required to be paid to or for the account of the Liquidity
Provider on or prior to the Effective Date.

      (d) All conditions precedent to the issuance of the Class C Certificates
under the Class C Trust Agreement shall have been satisfied or waived, and all
conditions precedent to the effectiveness of the other Liquidity Facilities
shall have been satisfied or waived, and all conditions precedent to the
purchase of the Class C Certificates by Airbus Industrie Financial Services
under the Purchase Agreement shall have been satisfied (unless any of such
conditions precedent shall have been waived by Airbus Industrie Financial
Services).
<PAGE>

      (e) The Borrower shall have received a certificate, dated the date hereof,
signed by a duly authorized representative of the Liquidity Provider, certifying
that all conditions precedent to the effectiveness of Section 2.01 have been
satisfied or waived.

      (f) The Borrower shall have received the Guarantee Agreement,
substantially in the form of Exhibit I hereto, duly executed on behalf of the
party thereto.

      Section 4.02. Conditions Precedent to Borrowing. The obligation of the
Liquidity Provider to make an Advance on the occasion of each Borrowing shall be
subject to the conditions precedent that the Effective Date shall have occurred
and, prior to the date of such Borrowing, the Borrower shall have delivered a
Notice of Borrowing which conforms to the terms and conditions of this Agreement
and has been completed as may be required by the relevant form of the Notice of
Borrowing for the type of Advances requested.

                                    ARTICLE V

                                    COVENANTS

      Section 5.01. Affirmative Covenants of the Borrower. So long as any
Advance shall remain unpaid or the Liquidity Provider shall have any Maximum
Commitment hereunder or the Borrower shall have any obligation to pay any amount
to the Liquidity Provider hereunder, the Borrower will, unless the Liquidity
Provider shall otherwise consent in writing:

      (a) Performance of This and Other Agreements. Punctually pay or cause to
be paid all amounts payable by it under this Agreement and the other Operative
Agreements and observe and perform in all material respects the conditions,
covenants and requirements applicable to it contained in this Agreement and the
other Operative Agreements.

      (b) Reporting Requirements. Furnish to the Liquidity Provider with
reasonable promptness, such other information and data with respect to the
transactions contemplated by the Operative Agreements as from time to time may
be reasonably requested by the Liquidity Provider; and permit the Liquidity
Provider, upon reasonable notice, to inspect the Borrower's books and records
with respect to such transactions and to meet with officers and employees of the
Borrower to discuss such transactions.

      (c) Certain Operative Agreements. Furnish to the Liquidity Provider with
reasonable promptness, such Operative Agreements entered into after the date
hereof as from time to time may be reasonably requested by the Liquidity
Provider.

      Section 5.02. Negative Covenants of the Borrower. So long as any Advance
shall remain unpaid or the Liquidity Provider shall have any Maximum Commitment
hereunder or the Borrower shall have any obligation to pay any amount to the
Liquidity Provider hereunder, the Borrower will not appoint or permit or suffer
to be appointed any successor Borrower without the prior written consent of the
Liquidity Provider, which consent shall not be unreasonably withheld or delayed.

                                   ARTICLE VI

                           LIQUIDITY EVENTS OF DEFAULT

      Section 6.01. Liquidity Events of Default. If (a) any Liquidity Event of
Default has occurred and is continuing and (b) there is
<PAGE>

a Performing Note Deficiency, the Liquidity Provider may, in its discretion,
deliver to the Borrower a Termination Notice, the effect of which shall be to
cause (i) the obligation of the Liquidity Provider to make Advances hereunder to
expire on the fifth Business Day after the date on which such Termination Notice
is received by the Borrower, (ii) the Borrower to promptly request, and the
Liquidity Provider to promptly make, a Final Advance in accordance with Section
2.02(d) hereof and Section 3.6(i) of the Intercreditor Agreement, (iii) all
other outstanding Advances to be automatically converted into Final Advances for
purposes of determining the Applicable Liquidity Rate for interest payable
thereon, and (iv) subject to Sections 2.07 and 2.09 hereof, all Advances
(including, without limitation, any Provider Advance and Applied Provider
Advance), any accrued interest thereon and any other amounts outstanding
hereunder to become immediately due and payable to the Liquidity Provider.

                                   ARTICLE VII

                                  MISCELLANEOUS

      Section 7.01. Amendments, Etc. No amendment or waiver of any provision of
this Agreement, nor consent to any departure by the Borrower therefrom, shall in
any event be effective unless the same shall be in writing and signed by the
Liquidity Provider, and, in the case of an amendment or of a waiver by the
Borrower, the Borrower, and then such waiver or consent shall be effective only
in the specific instance and for the specific purpose for which given.

      Section 7.02. Notices, Etc. Except as otherwise expressly provided herein,
all notices and other communications provided for hereunder shall be in writing
(including telecopier and mailed or delivered or sent by telecopier):

    Borrower:             State Street Bank and Trust Company of
                              Connecticut, National Association
                          225 Asylum Street
                          Goodwin Square
                          Hartford, CT  06103
                          Attention: Corporate/Muni. Department
                          Telephone: (860) 244-1822
                          Telecopy: (860) 244-1889

                          with a copy to:

                          State Street Bank and Trust Company
                          Corporate Trust Department
                          2 Avenue de Lafayette
                          Boston, MA  02110

                          Attention: Ruth A. Smith
                          Telecopy: (617) 662-1465

    Liquidity Provider:   Morgan Stanley Capital Services Inc.
                          1585 Broadway
                          New York, NY  10036

                          Attention: [Elinor Hoover/Ivana Komarcevic/
                          Mark Esparrago]
                          Telephone: (212) 761-2522/1895/2618
                          Telecopy: (302) 651-8882
<PAGE>

with a copy of any Notice of Borrowing to:

                               Morgan Stanley Dean Witter & Co.
                               1585 Broadway
                               3rd Floor
                               New York, NY  10036

                               Attention: James Hill, Legal Department
                               Telephone: (212) 762-6829
                               Telecopy: (212) 762-8896

or, as to each of the foregoing, at such other address as shall be
designated by such Person in a written notice to the others. All such
notices and communications shall be effective (i) if given by telecopier,
when transmitted to the telecopier number specified above and (ii) if given
by other means, when delivered at the address specified above, except that
written notices to the Liquidity Provider pursuant to the provisions of
Articles II and III hereof shall not be effective until received by the
Liquidity Provider. A copy of all notices delivered hereunder to either
party shall in addition be delivered to each of the parties to the
Participation Agreements at their respective addresses set forth therein.

      Section 7.03. No Waiver; Remedies. No failure on the part of the Liquidity
Provider to exercise, and no delay in exercising, any right under this Agreement
shall operate as a waiver thereof; nor shall any single or partial exercise of
any right under this Agreement preclude any other or further exercise thereof or
the exercise of any other right. The remedies herein provided are cumulative and
not exclusive of any remedies provided by law.

      Section 7.04. Further Assurances. The Borrower agrees to do such further
acts and things and to execute and deliver to the Liquidity Provider such
additional assignments, agreements, powers and instruments as the Liquidity
Provider may reasonably require or deem advisable to carry into effect the
purposes of this Agreement and the other Operative Agreements or to better
assure and confirm unto the Liquidity Provider its rights, powers and remedies
hereunder and under the other Operative Agreements.

      Section 7.05. Indemnification; Survival of Certain Provisions. The
Liquidity Provider shall be indemnified hereunder to the extent and in the
manner described in Section 6(c) of the Leased Aircraft Participation
Agreements, Section 6(b) of the Owned Aircraft Participation Agreements or
Section 7(c) of the Note Purchase Agreement, as the case may be. In addition,
the Borrower agrees to indemnify, protect, defend and hold harmless the
Liquidity Provider from, against and in respect of, and shall pay on demand, all
Expenses of any kind or nature whatsoever (other than any Expenses of the nature
described in Section 3.01, 3.02 or 7.07 hereof or in the Liquidity Facility Fee
Letter applicable to this Agreement (regardless of whether indemnified against
pursuant to said Sections or in such Liquidity Facility Fee Letter)), that may
be imposed, incurred by or asserted against any Liquidity Indemnitee, in any way
relating to, resulting from, or arising out of or in connection with any action,
suit or proceeding by any third party against such Liquidity Indemnitee and
relating to this Agreement, the Liquidity Facility Fee Letter applicable to this
Agreement, the Intercreditor Agreement or any Financing Agreement; provided,
however, that the Borrower shall not be required to indemnify, protect, defend
and hold harmless any Liquidity Indemnitee in respect of any Expense of such
Liquidity Indemnitee to the extent such Expense is (i) attributable to the gross
negligence or willful misconduct of such Liquidity Indemnitee or any other
Liquidity Indemnitee, (ii) ordinary and usual operating overhead expense, or
(iii) attributable to the failure by such Liquidity Indemnitee or any other
Liquidity Indemnitee to perform or
<PAGE>

observe any agreement, covenant or condition on its part to be performed or
observed in this Agreement, the Intercreditor Agreement, the Liquidity Facility
Fee Letter applicable to this Agreement or any other Operative Agreement to
which it is a party. The indemnities contained in Section 6(c) of the Leased
Aircraft Participation Agreements or 6(b) of the Owned Aircraft Participation
Agreements, as the case may be, and the provisions of Sections 3.01, 3.02, 3.03,
3.09, 7.05 and 7.07 hereof, shall survive the termination of this Agreement.

      Section 7.06. Liability of the Liquidity Provider. (a) Neither the
Liquidity Provider nor any of its officers, employees, directors or Affiliates
shall be liable or responsible for: (i) the use which may be made of the
Advances or any acts or omissions of the Borrower or any beneficiary or
transferee in connection therewith; (ii) the validity, sufficiency or
genuineness of documents, or of any endorsement thereon, even if such documents
should prove to be in any or all respects invalid, insufficient, fraudulent or
forged; or (iii) the making of Advances by the Liquidity Provider against
delivery of a Notice of Borrowing and other documents which do not comply with
the terms hereof; provided, however, that the Borrower shall have a claim
against the Liquidity Provider, and the Liquidity Provider shall be liable to
the Borrower, to the extent of any damages suffered by the Borrower which were
the result of (A) the Liquidity Provider's willful misconduct or negligence in
determining whether documents presented hereunder comply with the terms hereof,
or (B) any breach by the Liquidity Provider of any of the terms of this
Agreement, including, but not limited to, the Liquidity Provider's failure to
make lawful payment hereunder after the delivery to it by the Borrower of a
Notice of Borrowing strictly complying with the terms and conditions hereof.

      (b) Neither the Liquidity Provider nor any of its officers, employees,
directors or Affiliates shall be liable or responsible in any respect for (i)
any error, omission, interruption or delay in transmission, dispatch or delivery
of any message or advice, however transmitted, in connection with this Agreement
or any Notice of Borrowing delivered hereunder, or (ii) any action, inaction or
omission which may be taken by it in good faith, absent willful misconduct or
negligence (in which event the extent of the Liquidity Provider's potential
liability to the Borrower shall be limited as set forth in the immediately
preceding paragraph), in connection with this Agreement or any Notice of
Borrowing.

      Section 7.07. Costs, Expenses and Taxes. The Borrower agrees to pay, or
cause to be paid (A) on the Effective Date and on such later date or dates on
which the Liquidity Provider shall make demand, all reasonable out-of-pocket
costs and expenses (including, without limitation, the reasonable fees and
expenses of outside counsel for the Liquidity Provider) of the Liquidity
Provider in connection with the preparation, negotiation, execution, delivery,
filing and recording of this Agreement, any other Operative Agreement and any
other documents which may be delivered in connection with this Agreement and (B)
on demand, all reasonable costs and expenses (including reasonable counsel fees
and expenses) of the Liquidity Provider in connection with (i) the enforcement
of this Agreement or any other Operative Agreement, (ii) the modification or
amendment of, or supplement to, this Agreement or any other Operative Agreement
or such other documents which may be delivered in connection herewith or
therewith (whether or not the same shall become effective) or (iii) any action
or proceeding relating to any order, injunction, or other process or decree
restraining or seeking to restrain the Liquidity Provider from paying any amount
under this Agreement, the Intercreditor Agreement or any other Operative
Agreement or otherwise affecting the application of funds in the Class C Cash
Collateral Account. In addition, the Borrower shall pay any and all recording,
stamp and other similar taxes and fees payable or determined to be payable in
connection with the execution,
<PAGE>

delivery, filing and recording of this Agreement, any other Operative Agreement
and such other documents, and agrees to save the Liquidity Provider harmless
from and against any and all liabilities with respect to or resulting from any
delay in paying or omission to pay such taxes or fees.

      Section 7.08. Binding Effect; Participations. (a) This Agreement shall be
binding upon and inure to the benefit of the Borrower and the Liquidity Provider
and their respective successors and assigns, except that neither the Liquidity
Provider (except as otherwise provided in this Section 7.08) nor (except as
contemplated by Section 3.08) the Borrower shall have the right to assign its
rights or obligations hereunder or any interest herein without the prior written
consent of the other party, subject to the requirements of Section 7.08(b). The
Liquidity Provider may grant participations herein or in any of its rights
hereunder (including, without limitation, funded participations and
participations in rights to receive interest payments hereunder) and under the
other Operative Agreements to such Persons (other than US Airways or any of its
affiliates) as the Liquidity Provider may in its sole discretion select, subject
to the requirements of Section 7.08(b). No such participation by the Liquidity
Provider, however, will relieve the Liquidity Provider of its obligations
hereunder. In connection with any participation or any proposed participation,
the Liquidity Provider may disclose to the participant or the proposed
participant any information that the Borrower is required to deliver or to
disclose to the Liquidity Provider pursuant to this Agreement. The Borrower
acknowledges and agrees that the Liquidity Provider's source of funds may derive
in part from its participants. Accordingly, references in this Agreement and the
other Operative Agreements to determinations, reserve and capital adequacy
requirements, increased costs, reduced receipts, additional amounts due pursuant
to Section 3.03(a) and the like as they pertain to the Liquidity Provider shall
be deemed also to include those of each of its participants that are banks
(subject, in each case, if any such participant is not a bank that is (i)
organized under the laws of the United States or any State thereof and (ii) a
member bank of the Federal Reserve System with deposits exceeding $1,000,000,000
(such a bank, a "Reference Bank"), to the maximum amount that would have been
directly incurred by any Reference Bank organized under the laws of the United
States or any State thereof if such Reference Bank, rather than the participant,
had held the interest participated).

      (b) If, pursuant to subsection (a) above, the Liquidity Provider sells any
participation in this Agreement to any bank or other entity (each, a
"Transferee"), then, concurrently with the effectiveness of such participation,
the Transferee shall (i) represent to the Liquidity Provider (for the benefit of
the Liquidity Provider and the Borrower) either (A) that it is incorporated
under the laws of the United States or a state thereof or (B) that under
applicable law and treaties, no taxes will be required to be withheld with
respect to any payments to be made to such Transferee in respect of this
Agreement, (ii) furnish to the Liquidity Provider and the Borrower either (x) a
statement that it is incorporated under the laws of the United States or a state
thereof or (y) if it is not so incorporated, two copies of a properly completed
United States Internal Revenue Service Form W-8ECI or Form W-8BEN, as
appropriate, or other applicable form, certificate or document prescribed by the
Internal Revenue Service certifying, in each case, such Transferee's entitlement
to a complete exemption from United States federal withholding tax in respect to
any and all payments to be made hereunder, and (iii) agree (for the benefit of
the Liquidity Provider and the Borrower) to provide the Liquidity Provider and
the Borrower a new Form W-8ECI or Form W-8BEN, as appropriate, (A) on or before
the date that any such form expires or becomes obsolete or (B) after the
occurrence of any event requiring a change in the most recent form previously
delivered by it and prior to the immediately following due date of any payment
by the Borrower hereunder, certifying in the case of a
<PAGE>

Form W-8BEN or Form W-8ECI that such Transferee is entitled to a complete
exemption from United States federal withholding tax on payments under this
Agreement. Unless the Borrower has received forms or other documents reasonably
satisfactory to it (and required by applicable law) indicating that payments
hereunder are not subject to United States federal withholding tax, the Borrower
will withhold taxes as required by law from such payments at the applicable
statutory rate.

      (c) Notwithstanding the other provisions of this Section 7.08, the
Liquidity Provider may assign and pledge all or any portion of the Advances
owing to it to any Federal Reserve Bank or the United States Treasury as
collateral security pursuant to Regulation A of the Board of Governors of the
Federal Reserve System and any Operating Circular issued by such Federal Reserve
Bank, provided that any payment in respect of such assigned Advances made by the
Borrower to the Liquidity Provider in accordance with the terms of this
Agreement shall satisfy the Borrower's obligations hereunder in respect of such
assigned Advance to the extent of such payment. No such assignment shall release
the Liquidity Provider from its obligations hereunder.

      Section 7.09. Severability. Any provision of this Agreement which is
prohibited, unenforceable or not authorized in any jurisdiction shall, as to
such jurisdiction, be ineffective to the extent of such prohibition,
unenforceability or non-authorization without invalidating the remaining
provisions hereof or affecting the validity, enforceability or legality of such
provision in any other jurisdiction.

      Section 7.10. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

      Section 7.11. Submission to Jurisdiction; Waiver of Jury Trial; Waiver of
Immunity. (a) Each of the parties hereto hereby irrevocably and unconditionally:

      (i)   submits for itself and its property in any legal action or
            proceeding relating to this Agreement or any other Operative
            Agreement, or for recognition and enforcement of any judgment in
            respect hereof or thereof, to the nonexclusive general jurisdiction
            of the courts of the State of New York, the courts of the United
            States of America for the Southern District of New York, and the
            appellate courts from any thereof;

      (ii)  consents that any such action or proceeding may be brought in such
            courts, and waives any objection that it may now or hereafter have
            to the venue of any such action or proceeding in any such court or
            that such action or proceeding was brought in an inconvenient court
            and agrees not to plead or claim the same;

      (iii) agrees that service of process in any such action or proceeding may
            be effected by mailing a copy thereof by registered or certified
            mail (or any substantially similar form of mail), postage prepaid,
            to each party hereto at its address set forth in Section 7.02
            hereof, or at such other address of which the Liquidity Provider
            shall have been notified pursuant thereto; and
<PAGE>

      (iv)  agrees that nothing herein shall affect the right to effect service
            of process in any other manner permitted by law or shall limit the
            right to sue in any other jurisdiction.

      (b) THE BORROWER AND THE LIQUIDITY PROVIDER EACH HEREBY AGREE TO WAIVE
THEIR RESPECTIVE RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED
UPON OR ARISING OUT OF THIS AGREEMENT OR ANY DEALINGS BETWEEN THEM RELATING TO
THE SUBJECT MATTER OF THIS AGREEMENT AND THE RELATIONSHIP THAT IS BEING
ESTABLISHED, including, without limitation, contract claims, tort claims, breach
of duty claims and all other common law and statutory claims. The Borrower and
the Liquidity Provider each warrant and represent that it has reviewed this
waiver with its legal counsel, and that it knowingly and voluntarily waives its
jury trial rights following consultation with such legal counsel. THIS WAIVER IS
IRREVOCABLE, AND CANNOT BE MODIFIED EITHER ORALLY OR IN WRITING, AND THIS WAIVER
SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS
TO THIS AGREEMENT.

      Section 7.12. Execution in Counterparts. This Agreement may be executed in
any number of counterparts and by different parties hereto on separate
counterparts, each of which counterparts, when so executed and delivered, shall
be deemed to be an original and all of which counterparts, taken together, shall
constitute but one and the same Agreement.

      Section 7.13. Entirety. This Agreement, the Intercreditor Agreement and
the other Operative Agreements to which the Liquidity Provider is a party
constitute the entire agreement of the parties hereto with respect to the
subject matter hereof and supersedes all prior understandings and agreements of
such parties.

      Section 7.14. Headings. Section headings in this Agreement are included
herein for convenience of reference only and shall not constitute a part of this
Agreement for any other purpose.

      Section 7.15. LIQUIDITY PROVIDER'S OBLIGATION TO MAKE ADVANCES. EXCEPT AS
EXPRESSLY SET FORTH IN THIS AGREEMENT, THE OBLIGATIONS OF THE LIQUIDITY PROVIDER
TO MAKE ADVANCES HEREUNDER, AND THE BORROWER'S RIGHTS TO DELIVER NOTICES OF
BORROWING REQUESTING THE MAKING OF ADVANCES HEREUNDER, SHALL BE UNCONDITIONAL
AND IRREVOCABLE, AND SHALL BE PAID OR PERFORMED, IN EACH CASE STRICTLY IN
ACCORDANCE WITH THE TERMS OF THIS AGREEMENT.
<PAGE>

      IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed and delivered by their respective officers thereunto duly authorized as
of the date first set forth above.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as agent and
                                          trustee for the Class C Trust, as
                                          Borrower

                                          By /s/ John G. Correia
                                             ----------------------------------
                                          Name: John G. Correia
                                          Title:   Assistant Vice President

                                          MORGAN STANLEY CAPITAL SERVICES INC.,
                                          as Liquidity Provider

                                          By /s/ Elinor L. Hoover
                                             ----------------------------------
                                          Name: Elinor L. Hoover
                                          Title: Vice President

<PAGE>

                                         Annex I to Revolving Credit Agreement

                      INTEREST ADVANCE NOTICE OF BORROWING

            The undersigned, a duly authorized signatory of the undersigned
borrower (the "Borrower"), hereby certifies to Morgan Stanley Capital Services
Inc. (the "Liquidity Provider"), with reference to the Revolving Credit
Agreement (2000-3C) dated as of November 2, 2000, between the Borrower and the
Liquidity Provider (the "Liquidity Agreement"; the terms defined therein and not
otherwise defined herein being used herein as therein defined or referenced),
that:

            (1) The Borrower is the Subordination Agent under the Intercreditor
      Agreement.

            (2) The Borrower is delivering this Notice of Borrowing for the
      making of an Interest Advance by the Liquidity Provider to be used,
      subject to clause (3)(v) below, for the payment of the interest on the
      Class C Certificates which was payable on ____________, ____ (the
      "Distribution Date") in accordance with the terms and provisions of the
      Class C Trust Agreement and the Class C Certificates, which Advance is
      requested to be made on ____________, ____. The Interest Advance should be
      transferred to [name of bank/wire instructions/ABA number] in favor of
      account number [ __ ], reference [ __ ].

            (3) The amount of the Interest Advance requested hereby (i) is
      $_______________.__, to be applied in respect of the payment of the
      interest which is due and payable on the Class C Certificates on the
      Distribution Date, (ii) does not include any amount with respect to the
      payment of principal of, or premium on, the Class C Certificates or the
      Class G Certificates, or interest on the Class G Certificates, (iii) was
      computed in accordance with the provisions of the Class C Certificates,
      the Class C Trust Agreement and the Intercreditor Agreement (a copy of
      which computation is attached hereto as Schedule I), (iv) does not exceed
      the Maximum Available Commitment on the date hereof, (v) does not include
      any amount of interest which was due and payable on the Class C
      Certificates on such Distribution Date but which remains unpaid due to the
      failure of the Depositary to pay any amount of accrued interest on the
      Deposits on such Distribution Date and (vi) has not been and is not the
      subject of a prior or contemporaneous Notice of Borrowing.

            (4) Upon receipt by or on behalf of the Borrower of the amount
      requested hereby, (a) the Borrower will apply the same in accordance with
      the terms of Section 3.6(b) of the Intercreditor Agreement, (b) no portion
      of such amount shall be applied by the Borrower for any other purpose and
      (c) no portion of such amount until so applied shall be commingled with
      other funds held by the Borrower.

            The Borrower hereby acknowledges that, pursuant to the Liquidity
Agreement, the making of the Interest Advance as requested by this Notice of
Borrowing shall automatically reduce, subject to reinstatement in accordance
with the terms of the Liquidity Agreement, the Maximum Available Commitment by
an amount equal to the amount of the Interest Advance requested to be made
hereby as set forth in clause (i) of paragraph (3) of this Notice of Borrowing
and such reduction shall automatically result in corresponding reductions in the
amounts available to be borrowed pursuant to a subsequent Advance.
<PAGE>

            IN WITNESS WHEREOF, the Borrower has executed and delivered this
Notice of Borrowing as of the ____ day of __________, ____.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as Borrower

                                          By: _______________________________
                                          Name:
                                          Title:

<PAGE>

               SCHEDULE I TO INTEREST ADVANCE NOTICE OF BORROWING

 [Insert Copy of Computations in accordance with Interest Advance Notice
of Borrowing]
<PAGE>

                                                                    Annex II to
                                                     Revolving Credit Agreement

                  NON-EXTENSION ADVANCE NOTICE OF BORROWING

            The undersigned, a duly authorized signatory of the undersigned
borrower (the "Borrower"), hereby certifies to Morgan Stanley Capital Services
Inc. (the "Liquidity Provider"), with reference to the Revolving Credit
Agreement (2000-3C) dated as of November 2, 2000, between the Borrower and the
Liquidity Provider (the "Liquidity Agreement"; the terms defined therein and not
otherwise defined herein being used herein as therein defined or referenced),
that:

            (1) The Borrower is the Subordination Agent under the Intercreditor
      Agreement.

            (2) The Borrower is delivering this Notice of Borrowing for the
      making of the Non-Extension Advance by the Liquidity Provider to be used
      for the funding of the Class C Cash Collateral Account in accordance with
      Section 3.6(d) of the Intercreditor Agreement, which Advance is requested
      to be made on __________, ____. The Non-Extension Advance should be
      transferred to [name of bank/wire instructions/ABA number] in favor of
      account number [ __ ], reference [ __ ].

            (3) The amount of the Non-Extension Advance requested hereby (i) is
      $_______________.__, which equals the Maximum Available Commitment on the
      date hereof and is to be applied in respect of the funding of the Class C
      Cash Collateral Account in accordance with Section 3.6(d) of the
      Intercreditor Agreement, (ii) does not include any amount with respect to
      the payment of the principal of, or premium on, the Class C Certificates
      or the Class G Certificates, or interest on the Class G Certificates,
      (iii) was computed in accordance with the provisions of the Class C
      Certificates, the Class C Trust Agreement and the Intercreditor Agreement
      (a copy of which computation is attached hereto as Schedule I), and (iv)
      has not been and is not the subject of a prior or contemporaneous Notice
      of Borrowing under the Liquidity Agreement.

            (4) Upon receipt by or on behalf of the Borrower of the amount
      requested hereby, (a) the Borrower will deposit such amount in the Class C
      Cash Collateral Account and apply the same in accordance with the terms of
      Section 3.6(d) of the Intercreditor Agreement, (b) no portion of such
      amount shall be applied by the Borrower for any other purpose and (c) no
      portion of such amount until so applied shall be commingled with other
      funds held by the Borrower.

            The Borrower hereby acknowledges that, pursuant to the Liquidity
Agreement, (A) the making of the Non-Extension Advance as requested by this
Notice of Borrowing shall automatically and irrevocably terminate the obligation
of the Liquidity Provider to make further Advances under the Liquidity
Agreement; and (B) following the making by the Liquidity Provider of the
Non-Extension Advance requested by this Notice of Borrowing, the Borrower shall
not be entitled to request any further Advances under the Liquidity Agreement.

            IN WITNESS WHEREOF, the Borrower has executed and delivered this
Notice of Borrowing as of the ____ day of __________, ____.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as Borrower

                                          By: ________________________________
                                          Name:
                                          Title:

<PAGE>

          SCHEDULE I TO NON-EXTENSION ADVANCE NOTICE OF BORROWING

 [Insert Copy of computations in accordance with Non-Extension Advance Notice
of Borrowing]

<PAGE>

                                                                    Annex III to
                                                      Revolving Credit Agreement

                      DOWNGRADE ADVANCE NOTICE OF BORROWING

            The undersigned, a duly authorized signatory of the undersigned
borrower (the "Borrower"), hereby certifies to Morgan Stanley Capital Services
Inc. (the "Liquidity Provider"), with reference to the Revolving Credit
Agreement (2000-3C) dated as of November 2, 2000, between the Borrower and the
Liquidity Provider (the "Liquidity Agreement"; the terms defined therein and not
otherwise defined herein being used herein as therein defined or referenced),
that:

            (1) The Borrower is the Subordination Agent under the Intercreditor
      Agreement.

            (2) The Borrower is delivering this Notice of Borrowing for the
      making of the Downgrade Advance by the Liquidity Provider to be used for
      the funding of the Class C Cash Collateral Account in accordance with
      Section 3.6(c) of the Intercreditor Agreement (i) by reason of the
      downgrading of the short-term unsecured debt rating of the Guarantor
      issued by either Rating Agency below the Threshold Rating or (ii) because
      the Guarantee Agreement has ceased to be in full force and effect or has
      become invalid or unenforceable or the Guarantor has denied its liability
      thereunder, which Advance is requested to be made on __________, ____. The
      Downgrade Advance should be transferred to [name of bank/wire
      instructions/ABA number] in favor of account number [ __ ], reference
      [ __ ].

            (3) The amount of the Downgrade Advance requested hereby (i) is
      $_______________.__, which equals the Maximum Available Commitment on the
      date hereof and is to be applied in respect of the funding of the Class C
      Cash Collateral Account in accordance with Section 3.6(c) of the
      Intercreditor Agreement, (ii) does not include any amount with respect to
      the payment of the principal of, or premium on, the Class C Certificates
      or the Class G Certificates, or interest on the Class G Certificates,
      (iii) was computed in accordance with the provisions of the Class G
      Certificates, the Class C Trust Agreement and the Intercreditor Agreement
      (a copy of which computation is attached hereto as Schedule I), and (iv)
      has not been and is not the subject of a prior or contemporaneous Notice
      of Borrowing under the Liquidity Agreement.

            (4) Upon receipt by or on behalf of the Borrower of the amount
      requested hereby, (a) the Borrower will deposit such amount in the Class C
      Cash Collateral Account and apply the same in accordance with the terms of
      Section 3.6(c) of the Intercreditor Agreement, (b) no portion of such
      amount shall be applied by the Borrower for any other purpose and (c) no
      portion of such amount until so applied shall be commingled with other
      funds held by the Borrower.

            The Borrower hereby acknowledges that, pursuant to the Liquidity
Agreement, (A) the making of the Downgrade Advance as requested by this Notice
of Borrowing shall automatically and irrevocably terminate the obligation of the
Liquidity Provider to make further Advances under the Liquidity Agreement; and
(B) following the making by the Liquidity Provider of the Downgrade Advance
requested by this Notice of Borrowing, the Borrower shall not be entitled to
request any further Advances under the Liquidity Agreement.
<PAGE>

            IN WITNESS WHEREOF, the Borrower has executed and delivered this
Notice of Borrowing as of the ____ day of _________, _____.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as Borrower

                                          By: _________________________________
                                          Name:
                                          Title:

<PAGE>

               SCHEDULE I TO DOWNGRADE ADVANCE NOTICE OF BORROWING

 [Insert Copy of computations in accordance with Downgrade Advance Notice
of Borrowing]
<PAGE>

                                                                     Annex IV to
                                                      Revolving Credit Agreement

                        FINAL ADVANCE NOTICE OF BORROWING

            The undersigned, a duly authorized signatory of the undersigned
borrower (the "Borrower"), hereby certifies to Morgan Stanley Capital Services
Inc. (the "Liquidity Provider"), with reference to the Revolving Credit
Agreement (2000-3C) dated as of November 2, 2000, between the Borrower and the
Liquidity Provider (the "Liquidity Agreement"; the terms defined therein and not
otherwise defined herein being used herein as therein defined or referenced),
that:

            (1) The Borrower is the Subordination Agent under the Intercreditor
      Agreement.

            (2) The Borrower is delivering this Notice of Borrowing for the
      making of the Final Advance by the Liquidity Provider to be used for the
      funding of the Class C Cash Collateral Account in accordance with Section
      3.6(i) of the Intercreditor Agreement by reason of the receipt by the
      Borrower of a Termination Notice from the Liquidity Provider with respect
      to the Liquidity Agreement, which Advance is requested to be made on
      ____________, ____. The Final Advance should be transferred to [name of
      bank/wire instructions/ABA number] in favor of account number [ __ ],
      reference [ __ ].

            (3) The amount of the Final Advance requested hereby (i) is
      $_________________.__, which equals the Maximum Available Commitment on
      the date hereof and is to be applied in respect of the funding of the
      Class C Cash Collateral Account in accordance with Section 3.6(i) of the
      Intercreditor Agreement, (ii) does not include any amount with respect to
      the payment of principal of, or premium on, the Class C Certificates or
      the Class G Certificates, or interest on the Class G Certificates, (iii)
      was computed in accordance with the provisions of the Class C
      Certificates, the Class C Trust Agreement and the Intercreditor Agreement
      (a copy of which computation is attached hereto as Schedule I), and (iv)
      has not been and is not the subject of a prior or contemporaneous Notice
      of Borrowing.

            (4) Upon receipt by or on behalf of the Borrower of the amount
      requested hereby, (a) the Borrower will deposit such amount in the Class C
      Cash Collateral Account and apply the same in accordance with the terms of
      Section 3.6(i) of the Intercreditor Agreement, (b) no portion of such
      amount shall be applied by the Borrower for any other purpose and (c) no
      portion of such amount until so applied shall be commingled with other
      funds held by the Borrower.

            (5) The Borrower hereby requests that the Advance requested hereby
      be a Base Rate Advance [and that such Base Rate Advance be converted into
      a LIBOR Advance on the third Business Day following your receipt of this
      notice]1.

            The Borrower hereby acknowledges that, pursuant to the Liquidity
Agreement, (A) the making of the Final Advance as requested by this Notice of
Borrowing shall automatically and irrevocably terminate the obligation of the
Liquidity Provider to make further Advances under the Liquidity Agreement; and
(B) following the making by the Liquidity Provider of the Final Advance
requested by this Notice of Borrowing, the Borrower shall not be entitled to
request any further Advances under the Liquidity Agreement.

            IN WITNESS WHEREOF, the Borrower has executed and delivered this
Notice of Borrowing as of the ____ day of ___________, ____.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as Borrower

                                          By _________________________________
                                          Name:
                                          Title:

<PAGE>

                 SCHEDULE I TO FINAL ADVANCE NOTICE OF BORROWING

 [Insert Copy of Computations in accordance with Final Advance Notice of
Borrowing]
<PAGE>

                                                                      Annex V to
                                                      Revolving Credit Agreement

                              NOTICE OF TERMINATION

                                                       [Date]

State Street Bank and Trust Company of
   Connecticut, National Association,
   as Subordination Agent, as Borrower
225 Asylum Street
Goodwin Square
Hartford, CT  06103

Attention:  Corporate Trust Administration

            Revolving Credit Agreement dated as of November 2, 2000, between
            State Street Bank and Trust Company of Connecticut, National
            Association, as Subordination Agent, as agent and trustee for the US
            Airways Pass Through Trust, 2000-3C, as Borrower, and Morgan Stanley
            Capital Services Inc. (the "Liquidity Agreement")

Ladies and Gentlemen:

            You are hereby notified that pursuant to Section 6.01 of the
Liquidity Agreement, by reason of the occurrence of a Liquidity Event of Default
and the existence of a Performing Note Deficiency (each as defined therein), we
are giving this notice to you in order to cause (i) our obligations to make
Advances (as defined therein) under such Liquidity Agreement to terminate on the
fifth Business Day after the date on which you receive this notice and (ii) you
to request a Final Advance under the Liquidity Agreement pursuant to Section
3.6(i) of the Intercreditor Agreement (as defined in the Liquidity Agreement) as
a consequence of your receipt of this notice.

            THIS NOTICE IS THE "NOTICE OF TERMINATION" PROVIDED FOR UNDER THE
LIQUIDITY AGREEMENT. OUR OBLIGATIONS TO MAKE ADVANCES UNDER THE LIQUIDITY
AGREEMENT WILL TERMINATE ON THE FIFTH BUSINESS DAY AFTER THE DATE ON WHICH YOU
RECEIVE THIS NOTICE.

                                          Very truly yours,

                                          Morgan Stanley Capital Services Inc.,
                                          as Liquidity Provider

                                          By ________________________________
                                          Name:
                                          Title:

cc: State Street Bank and Trust Company of
    Connecticut, National Association,
    as Class C Trustee

<PAGE>

                                                                   Annex VI to
                                                    Revolving Credit Agreement

                 NOTICE OF REPLACEMENT SUBORDINATION AGENT

[Date]
Attention:

         Revolving Credit Agreement dated as of November 2, 2000, between
         State Street Bank and Trust Company of Connecticut, National
         Association, as Subordination Agent, as agent and trustee for the
         US Airways Pass Through Trust, 2000-3C, as Borrower, and Morgan
         Stanley Capital Services Inc. (the "Liquidity Agreement")

Ladies and Gentlemen:

         For value received, the undersigned beneficiary hereby irrevocably
transfers to:

                        ____________________________
                            [Name of Transferee]

                        ____________________________
                          [Address of Transferee]

all rights and obligations of the undersigned as Borrower under the
Liquidity Agreement referred to above. The transferee has succeeded the
undersigned as Subordination Agent under the Intercreditor Agreement
referred to in the first paragraph of the Liquidity Agreement, pursuant to
the terms of Section 8.1 of the Intercreditor Agreement.

            By this transfer, all rights of the undersigned as Borrower under
the Liquidity Agreement are transferred to the transferee and the transferee
shall hereafter have the sole rights and obligations as Borrower thereunder. The
undersigned shall pay any costs and expenses of such transfer, including, but
not limited to, transfer taxes or governmental charges.

<PAGE>

            We ask that this transfer be effective as of _______________, ____.

                                          STATE STREET BANK AND TRUST
                                          COMPANY OF CONNECTICUT, NATIONAL
                                          ASSOCIATION, not in its
                                          individual capacity but solely as
                                          Subordination Agent, as Borrower

                                          By _________________________________
                                          Name:
                                          Title:

                                          By _________________________________
                                          Name:
                                          Title:

<PAGE>

                                                                  EXHIBIT I to
                                                    Revolving Credit Agreement

                           FORM OF GUARANTEE AGREEMENT

                                              _________ __, 2000

US Airways Pass Through Trust 2000-3C
Ladies and Gentlemen:

      In consideration of the Revolving Credit Agreement (the "Agreement") dated
as of _____ __, 2000 between Morgan Stanley Capital Services Inc., a Delaware
corporation (hereinafter "MSCS") and State Street Bank and Trust Company of
Connecticut, National Association, as Subordination Agent, as agent and trustee
for the US Airways Pass Through Trust 2000-3C ("Counterparty"), Morgan Stanley
Dean Witter & Co., a Delaware corporation (hereinafter "MSDW"), hereby
irrevocably and unconditionally guarantees to Counterparty, with effect from the
date of the Agreement, the due and punctual payment of all amounts payable by
MSCS under the Agreement when the same shall become due and payable, whether on
scheduled payment dates, upon demand, upon declaration of termination or
otherwise, in accordance with the terms of the Agreement and giving effect to
any applicable grace period under the express terms of the Agreement. Upon
failure of MSCS punctually to pay any such amounts, MSDW agrees to pay or cause
to be paid such amounts. It is understood and agreed that the obligations of
MSCS under the Agreement to make Advances (as defined in the Agreement) are, and
shall in any event, for all purposes of the Guarantee, be deemed to constitute,
amounts payable by MSCS under the Agreement.

      MSDW hereby agrees that its obligations hereunder shall be unconditional
and will not be discharged except by complete payment of the amounts payable
under the Agreement, irrespective of any claim as to the Agreement's validity,
regularity or enforceability or the lack of authority of MSCS to execute or
deliver the Agreement; or any change in or amendment to the Agreement; or any
waiver or consent by Counterparty with respect to any provisions thereof; or the
absence of any action to enforce the Agreement or the recovery of any judgment
against MSCS or of any action to enforce a judgment against MSCS under the
Agreement; or any similar circumstance which might otherwise constitute a legal
or equitable discharge or defense of a guarantor generally. MSDW hereby waives
diligence, presentment, demand on MSDW or MSCS for payment or otherwise, filing
of claims, requirement of a prior proceeding against MSCS and protest or notice,
except as provided for in the Agreement with respect to amounts payable by MSCS.
If at any time payment under the Agreement is rescinded or must be otherwise
restored or returned by Counterparty upon the insolvency, bankruptcy or
reorganization of MSCS or MSDW or otherwise, MSDW's obligations hereunder with
respect to such payment shall be reinstated upon such restoration or return
being made by Counterparty.

<PAGE>

      MSDW represents to Counterparty as of the date hereof that:

      (1) it is duly organized and validly existing under the laws of the
jurisdiction of its incorporation and has full power and legal right to execute
and deliver this Guarantee and to perform the provisions of this Guarantee on
its part to be performed;

      (2) its execution, delivery and performance of this Guarantee have been
and remain duly authorized by all necessary corporate action and do not
contravene any provision of its certificate of incorporation or by-laws or any
law, regulation or contractual restriction binding on it or its assets;

      (3) all consents, authorizations, approvals and clearances (including,
without limitation, any necessary exchange control approval) and notifications,
reports and registrations requisite for its due execution, delivery and
performance of this Guarantee have been obtained from or, as the case may be,
filed with the relevant governmental authorities having jurisdiction and remain
in full force and effect and all conditions thereof have been duly complied with
and no other action by, and no notice to or filing with, any governmental
authority having jurisdiction is required for such execution, delivery or
performance; and

      (4) this Guarantee is its legal, valid and binding obligation enforceable
against it in accordance with its terms except as enforcement hereof may be
limited by applicable bankruptcy, insolvency, reorganization or other similar
laws affecting the enforcement of creditors' rights or by general equity
principles.

      By accepting this Guarantee and entering into the Agreement, Counterparty
agrees that MSDW shall be subrogated to all rights of Counterparty against MSCS
in respect of any amounts paid by MSDW pursuant to this Guarantee, provided that
MSDW shall be entitled to enforce or to receive any payment arising out of or
based upon such right of subrogation only to the extent that it has paid all
amounts payable by MSCS under the Agreement.

      This Guarantee shall be governed by and construed in accordance with the
laws of the State of New York. All capitalized terms not otherwise defined
herein shall have the respective meanings assigned to them in the Agreement.

                                          MORGAN STANLEY DEAN WITTER & CO.

                                          By _____________________________
                                          Name:
                                          Title:

                                          Address: 1585 Broadway
                                                   3rd Floor
                                                   New York, NY  10036
                                          Attention: Swap Group
                                          Fax No.: (212) 761-0162

--------
1  Bracketed language may be included at Borrower's option.

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