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                                                                Exhibit 10.13(k)

              AMENDMENT NUMBER 11 TO PURCHASE AGREEMENT GCT-025/98

This Amendment Number 11 to Purchase Agreement GCT-025/98, dated as of May __,
2001 ("Amendment No. 11") relates to the Purchase Agreement GCT-025/98 (the
"Purchase Agreement") between EMBRAER - Empresa Brasileira de Aeronautica S.A.
("Embraer") and Solitair Corp. ("Buyer") dated June 17, 1998 as amended from
time to time (collectively referred to herein as "Agreement"). This Amendment
No. 11 is between Embraer and Buyer, collectively referred to herein as the
"Parties".

This Amendment No. 11 sets forth certain additional agreements between Embraer
and Buyer relative to changes on the delivery schedule, interest on late
payments and non-excusable delays interest for payments with maturity date on
and after January 31st, 2001 and Buyer's exercise of Option Aircraft.

This Amendment No. 11 constitutes an amendment and modification of the Purchase
Agreement. Except as otherwise provided for herein all terms of the Purchase
Agreement shall remain in full force and effect. All terms defined in this
Amendment No. 11 which are not defined in the Purchase Agreement shall have the
meaning set forth in this Amendment No. 11. All capitalized terms used in this
Amendment No. 11 which are not defined herein shall have the meaning given in
the Purchase Agreement. In the event of any conflict between this Amendment No.
11 and the Purchase Agreement the terms, conditions and provisions of this
Amendment No. 11 shall control.

WHEREAS, in connection with the Parties' agreements as described above, the
Parties have agreed to amend the Purchase Agreement as provided for below:

NOW, THEREFORE, for good and valuable consideration which is hereby acknowledged
Embraer and Buyer hereby agree as follows:

1.    In Article "4.c" - Late Payment and Termination for Failure to Make
      Payments, the interest Rate of [*] per month shall be deleted and
      replaced by [*] on the first and twenty-fifth lines of Article 4.c.

2.    AIRCRAFT DELIVERY SCHEDULE: The delivery schedule contained in Article
      "5.a" shall be deleted and replaced with the following:



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<Table>
<Caption>
     --------------------------------------------------------------------------------------------------------------------
         A/C #         DELIVERY MONTH        A/C #            DELIVERY MONTH            A/C #         DELIVERY MONTH
     --------------------------------------------------------------------------------------------------------------------
                                                                                         
          01              Apr-99*             16                 Nov-00*                 31             27 Jul-01
     --------------------------------------------------------------------------------------------------------------------
          02              Jun-99*             17                 Dec-00*                 32             24 Aug-01
     --------------------------------------------------------------------------------------------------------------------
          03              Aug-99*             18                 Dec-00*                 33             31 Aug-01
     --------------------------------------------------------------------------------------------------------------------
          04              Nov-99*             19                 Jan-01*                 34             21 Sep-01
     --------------------------------------------------------------------------------------------------------------------
          05              Jan-00*             20                 Jan-01*                 35             28 Sep-01
     --------------------------------------------------------------------------------------------------------------------
          06              Feb-00*             21                 Jan-01*                 36             12 Oct-01
     --------------------------------------------------------------------------------------------------------------------
          07              Mar-00*             22                 Feb-01*                 37             26 Oct-01
     --------------------------------------------------------------------------------------------------------------------
          08              May-00*             23                 Mar-01*                 38             16 Nov-01
     --------------------------------------------------------------------------------------------------------------------
          09              Jun-00*             24                 Apr-01*                 39             30 Nov-01
     --------------------------------------------------------------------------------------------------------------------
          10              Jul-00*             25                 Apr-01*                 40             20 Dec-01
     --------------------------------------------------------------------------------------------------------------------
          11              Aug-00*             26                 May-01*                 41             18 Jan-02
     --------------------------------------------------------------------------------------------------------------------
          12              Aug-00*             27                31 May-01                42             31 Jan-02
     --------------------------------------------------------------------------------------------------------------------
          13              Sep-00*             28                29 Jun-01                43             15 Feb-02
     --------------------------------------------------------------------------------------------------------------------
          14              Oct-00*             29                29 JUN-01                44             15 Mar-02
     --------------------------------------------------------------------------------------------------------------------
          15              Nov-00*             30                20 Jul-01                45             28 Mar-02
     --------------------------------------------------------------------------------------------------------------------
</Table>

REMARKS:  *Delivered to Buyer as of the date hereof.

3.    Article "9.b.1" shall be deleted and replaced with the following:

      "1.   If the delivery of an Aircraft or Spares is delayed, not as a result
            of an Excusable Delay, by more than [*] calendar days after
            the Contractual Delivery Date for such Aircraft or, in the case of
            Spares, the date for delivery as agreed between the Parties in
            accordance with Article 5.b., Buyer will be entitled to elect to
            receive in accordance with item "b.3" below from Embraer liquidated
            damages as compensation for such delay equal to [*] of each delayed
            Aircraft or the price of each Spares item, for each day of delay in
            excess of the above mentioned [*] calendar days, up to the
            date that the Aircraft is ready for delivery and available to Buyer
            by means of confirmation of the successful completion of ground and
            flight tests performed by Embraer, to be provided per Article 7.a,
            it being understood that such liquidated damages will not, in any
            event, [*] and that it will only be due and payable by Embraer to
            Buyer after Buyer pays to Embraer the total Aircraft Purchase Price
            and/or Spares items price as applicable. Such liquidated damages
            shall be paid at Buyer's option in cash or in the form of a credit
            for spare parts or other Embraer-provided services."

            3.1.  In Article 9.c - Delay Due to Loss or Structural Damage to the
                  Aircraft, the "...additional interest of [*]..." on
                  the sixteenth line shall be deleted and replaced by
                  "...additional interest of [*]...".


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4.    In the twenty seventh and twenty eighth lines of Article 23.b, eighteenth
      line of Article 23.b.1 and ninth and tenth lines of Article 23.d, the
      "...additional interest of [*]..." shall be deleted
      and replaced by "...additional interest of [*]...".

5.    The first paragraph of Article 24 shall be deleted and replaced with the
      following:

      "The Option Aircraft shall be divided into groups of a minimum of two (2)
      Aircraft. The groups shall be referred to collectively as the "Option
      Groups" and each may be referred to individually as an "Option Group".

      5.1.  Article 24.d.2 shall be deleted and replaced with the following;

      "2.   A progress payment of [*] defined in item "c" above, per exercised
            Option Aircraft, less the initial deposit of [*] is due and payable
            [*]

      5.2.  Article "24.e" shall be deleted and replaced with the following:

      "e.   CONFIRMATION OF OPTION GROUPS: Buyer's options to purchase Option
            Groups shall be confirmed on or before [*] in each Option Group.
            At the time of such confirmation, the Initial Deposit with respect
            to the Option Aircraft in such Option Group shall become non
            refundable. In the event that Buyer fails to exercise its option
            with respect to any [*]. The first Option Group shall be
            confirmed on or before [*]."

      5.3.  In Article 24.f - FAILURE TO CONFIRM: RETURN OF DEPOSIT, the
            "...additional interest of [*]..." on the eleventh line shall
            be deleted and replaced by "...additional interest of [*]...".

6.    MISCELLANEOUS

All other provisions of the Agreement which have not been specifically amended
or modified by this Amendment No. 11 shall remain valid in full force and effect
without any change.



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IN WITNESS WHEREOF, EMBRAER and BUYER, by their duly authorized officers, have
entered into and executed this Amendment No. 11 to be effective as of the date
first written above.

EMBRAER - Empresa Brasileira de                  Solitair Corp.
Aeronautica S.A.


By  /s/ Frederico Fleury Curado                  By  /s/ Douglas J. Lambert
  --------------------------------                 -----------------------------
Name:  Frederico Fleury Curado                   Name:  Douglas J. Lambert

Title: Executive Vice President                  Title: Vice President
           Airline Market

By  /s/ Flavio Rimoli                            Date:
  --------------------------------
Name:  Flavio Rimoli                             Place:

Title: Director of Contracts

Date:  June 29, 2001

Place: Sao Jose dos Campos