<PAGE>
                                                                    Exhibit 10.6

            *** CERTAIN CONFIDENTIAL INFORMATION HAS BEEN OMITTED AND
                FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
                    COMMISSION PURSUANT TO RULE 24b-2 OF THE
                   SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

                                Amendment No. 16

                    TO THE A319/A320/A321 PURCHASE AGREEMENT

                          dated as of October 31, 1997

                                     between

                                 AVSA, S.A.R.L.,

                                       And

                             US AIRWAYS GROUP, INC.

This Amendment No. 16 (this "Amendment") entered into as of September 27, 2005,
by and between AVSA, S.A.R.L., a societe a responsabilite limitee organized and
existing under the laws of the Republic of France, having its registered office
located at 2, Rond Point Maurice Bellonte, 31700 Blagnac, France (the "Seller"),
and US Airways Group, Inc., a corporation organized and existing under the laws
of the State of Delaware, United States of America, having its executive offices
located at 2345 Crystal Drive, Arlington, VA 22227, U.S.A. (the "Buyer");

WITNESSETH:

WHEREAS, the Buyer and the Seller entered into an Airbus A319/A320/A321 Purchase
Agreement, dated as of October 31, 1997, relating to the sale by the Seller and
the purchase by the Buyer of certain Airbus A319, A320 and A321 model aircraft
(the "Aircraft"), which, together with all Exhibits, Appendices and Letter
Agreements attached thereto and as amended by Amendment No. 1 dated as of June
10, 1998, Amendment No. 2 dated as of January 19, 1999, Amendment No. 3 dated as
of March 31, 1999, Amendment No. 4 dated as of August 31, 1999, Amendment No. 5
dated as of October 29, 1999, Amendment No. 6 dated as of April 19, 2000,
Amendment No. 7 dated as of June 29, 2000, Amendment No. 8 dated as of November
27, 2000, Amendment No. 9 dated as of December 29, 2000, Amendment No. 10 dated
as of April 9, 2001, Amendment No. 11 dated as of July 17, 2002, Amendment No.
12 dated as of March 29, 2003, Amendment No. 13 dated as of August 30, 2004,
Amendment No. 14 dated as of December 22, 2004, and Amendment No. 15 dated as of
January 17, 2005, thereto is hereinafter called the "Agreement";


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<PAGE>
WHEREAS, the Buyer and the Seller are parties to the Memorandum of Understanding
among the Seller, the Buyer, US Airways, Inc., and America West Airlines, Inc.,
bearing AVSA No. 5343 and signed by all the parties thereto as of May 19, 2005
(the "MOU"); and


WHEREAS, the Buyer has requested, and the Seller has agreed, on the terms and
conditions set forth in this Amendment, to modify certain provisions of the
Agreement as set forth herein;

NOW, THEREFORE, IT IS AGREED AS FOLLOWS:

Capitalized terms used herein and not otherwise defined in this Amendment will
have the meanings assigned to them in the Agreement. The terms "herein,"
"hereof," and "hereunder" and words of similar import refer to this Amendment.

1.    DEFINITIONS

      Clause 1 of the Agreement is hereby amended by the addition of the
      following text:

      QUOTE

      A350 Purchase Agreement - The A350 purchase agreement dated as of even
      date herewith among the Seller, the Buyer, US Airways, Inc., and America
      West Airlines, Inc. (the "A350 Purchase Agreement").

      UNQUOTE

2.    ASSUMPTION OF PURCHASE AGREEMENT

      The Buyer will assume the Agreement in connection with its emergence from
      the bankruptcy proceedings of the Buyer, US Airways, Inc. and certain of
      their affiliates commenced on September 12, 2004, in the United States
      Bankruptcy Court for the Eastern District of Virginia, Alexandria Division
      (the "Chapter 11 Case").

3.    CLAUSE 9 AND CLAUSE 3 OF PURCHASE AGREEMENT:  DELIVERY AND SPECIFICATION

3.1   The delivery schedule for the Aircraft as set forth in the Agreement is
      hereby deleted and replaced with the following:

      QUOTE

<TABLE>
<CAPTION>
      Aircraft No.                Type                  Scheduled Delivery Month
      ------------                ----                  ------------------------
<S>                               <C>                   <C>
      [...***...]
</TABLE>

***CONFIDENTIAL TREATMENT REQUESTED


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<PAGE>
      UNQUOTE

      The Aircraft shown in the table above are hereinafter referred to as the
      "Rescheduled Aircraft."

3.2   It is understood that the Buyer may from time to time desire to
      [...***...] the delivery of one or more Rescheduled Aircraft. The Seller
      agrees to continue to evaluate the availability of [...***...] delivery
      positions in light of the Seller's contractual commitments to other
      purchasers. For the avoidance of doubt, contractual commitments to other
      purchasers include [...***...].

3.3   In respect of the Rescheduled Aircraft, Clause 3.2 of the Agreement will
      be replaced with the following quoted text:

      QUOTE

      The Rescheduled Aircraft (as such term is defined in Amendment No. 16 to
      this Agreement) will be delivered based on the latest applicable standard
      specification available from the Manufacturer at the time the final
      definition of the Rescheduled Aircraft must be concluded, in order to
      accommodate timely manufacturing and delivery thereof (the "Latest
      Standard Specification"). The parties will execute all Manufacturer
      Specification Change Notices needed to amend the Standard Specification to
      the Latest Standard Specification (the "Required MSCNs"). Any and all
      costs associated with the incorporation of such Required MSCNs will be
      borne by the Seller, [...***...].

      UNQUOTE

3.4   [...***...]

4.    AMENDMENT 12:  LETTER AGREEMENT NO. 1

4.1   Paragraph 11.4 of Letter Agreement No. 1 of Amendment No. 12 to the
      Agreement is hereby deleted and replaced with the following:

QUOTE

11.4  [...***...]

UNQUOTE

4.2   [...***...]

5.    AMENDMENT 12:  LETTER AGREEMENT NO. 2

      The provisions of Letter Agreement No. 2 of Amendment No. 12 to the
      Agreement are hereby deleted in their entirety and of no further effect.

***CONFIDENTIAL TREATMENT REQUESTED


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<PAGE>
6.    PRICE REVISION

      The Final Contract Price for each Rescheduled Aircraft will be derived as
      provided in the Agreement, [...***...].

7.    [...***...]

8.    MISCELLANEOUS

      If the Buyer and/or US Airways, Inc. [...***...] of US Airways, Inc., at
      or prior to Bankruptcy Emergence, then, upon the satisfaction of the
      conditions set forth in Paragraph 9.1below [...***...].

9.    SPARES SUPPORT

      Effective on the later of (i) the date on which the Buyer or any of its
      Affiliate(s) and America West Airlines, Inc. operate under a common
      operating certificate as recognized by the Buyer's aviation authorities
      and (ii) December 31, 2007, then Paragraph 5.1 of Letter Agreement No. 1
      to the Agreement will be deleted and replaced with the following quoted
      text:

      QUOTE

      5.1 Point of Shipment

      [...***...]

      UNQUOTE

10.   EFFECT OF AMENDMENT

10.1  It will be a condition precedent to the effectiveness of this Amendment
      that the conditions precedent to (i) the validity of the A350 Purchase
      Agreement dated as of even date herewith have been satisfied, and (ii) the
      conditions precedent to the obligations of Airbus Financial Services (the
      "Lender") set forth in the $161,000,000 Loan Agreement dated as of
      September 27, 2005 among US Airways, Inc., America West Airlines, Inc., US
      Airways Group, Inc., the Lender and Wells Fargo Bank Northwest, National
      Association, as Collateral Agent, have been either satisfied or been
      waived by the Lender.

10.2  Upon effectiveness, the provisions of this Amendment will constitute a
      valid amendment to the Agreement and the Agreement will be deemed to be
      amended to the extent herein provided. This Amendment supersedes any
      previous understandings, commitments, or representations whatsoever,
      whether oral or written, related to the subject matter of this Amendment,
      including Paragraph 2 of the MOU.

***CONFIDENTIAL TREATMENT REQUESTED


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<PAGE>
10.3  Both parties agree that this Amendment will constitute an integral,
      nonseverable part of the Agreement, and that this Amendment will be
      governed by the provisions of the Agreement, except that if the Agreement
      and this Amendment have specific provisions that are inconsistent, the
      specific provisions contained in this Amendment will govern.

11.   GOVERNING LAW

      THIS AMENDMENT AND THE AGREEMENTS CONTEMPLATED HEREBY WILL, PURSUANT TO
      SECTION 5-1401 OF THE NEW YORK GENERAL OBLIGATIONS LAW, BE GOVERNED BY AND
      CONSTRUED AND THE PERFORMANCE THEREOF WILL BE DETERMINED IN ACCORDANCE
      WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT GIVING EFFECT TO ITS
      CONFLICTS OF LAWS PROVISION THAT WOULD RESULT IN THE APPLICATION OF THE
      LAW OF ANY OTHER JURISDICTION. EXCEPT TO THE EXTENT THAT THE BANKRUPTCY
      COURT IN THE CHAPTER 11 CASE HAS JURISDICTION THEREOF, ANY DISPUTE ARISING
      HEREUNDER WILL BE REFERRED TO THE FEDERAL OR STATE COURTS LOCATED IN NEW
      YORK CITY, NEW YORK, AND EACH OF THE PARTIES HERETO IRREVOCABLY SUBMITS TO
      AND ACCEPTS SUCH JURISDICTION.

      IT IS AGREED THAT THE UNITED NATIONS CONVENTION ON CONTRACTS FOR THE
      INTERNATIONAL SALE OF GOODS WILL NOT APPLY TO THIS AMENDMENT OR TO THE
      AGREEMENTS CONTEMPLATED HEREIN.

12.   CONFIDENTIALITY

      Notwithstanding the Confidentiality provisions of Clause 22.4 of the
      Agreement, the Seller and the Buyer (including their employees, agents and
      advisors) agree to keep the terms and conditions of this Amendment hereby
      strictly confidential, except as required by applicable law or pursuant to
      legal process, and except that the Buyer may disclose the terms of this
      Amendment to the parties to the ATSB loan agreement dated as of March 31,
      2003, as amended, and the committee professionals of the Unsecured
      Creditors Committee in the Chapter 11 Case and any proposed equity
      investor in the Buyer that is making its investment substantially
      contemporaneously as of the date hereof, provided, however, that each such
      person agrees to hold the terms and conditions of this Amendment
      confidential.

13.   COUNTERPARTS

      This Amendment may be signed in any number of separate counterparts. Each
      counterpart, when signed and delivered (including counterparts delivered
      by facsimile transmission), will be an original, and the counterparts will
      together constitute one same instrument.


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IN WITNESS WHEREOF, these presents were entered into as of the day and year
first above written.

      US AIRWAYS GROUP, INC.                    AVSA, S.A.R.L.


      By:                                       By:
         ----------------------------              -----------------------------


      Its:                                      Its:
          ---------------------------               ----------------------------


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