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Exhibit 10.21

THIRD AMENDMENT TO
NOTE PURCHASE AGREEMENT

    THIS THIRD AMENDMENT TO NOTE PURCHASE AGREEMENT, dated as of February 7,
2001 (this "Third Amendment"), is entered into by and among WLFC FUNDING
CORPORATION, as issuer (the "Issuer"), WILLIS LEASE FINANCE CORPORATION, as
servicer (the "Servicer"), VARIABLE FUNDING CAPITAL CORPORATION, as a purchaser
("VFCC"), the Investors, FIRST UNION SECURITIES, INC. (f/k/a First Union Capital
Markets Corp.), as deal agent (the "Deal Agent") and FIRST UNION NATIONAL BANK,
as liquidity agent ("FUNB"). Capitalized terms used and not otherwise defined
herein are used as defined in the Agreement (as defined below).

    WHEREAS, the parties hereto entered into that certain Note Purchase
Agreement, dated as February 11, 1999, as amended by the First Amendment, dated
as of May 12, 1999, and a Second Amendment, dated as of February 9, 2000 (the
"Agreement"); and

    WHEREAS, the parties hereto desire to amend the Agreement in certain
respects as provided herein;

    NOW THEREFORE, in consideration of the premises and the other mutual
covenants contained herein, the parties hereto agree as follows:

    SECTION 1.  Amendments.  

(a)The definition of "Commitment Termination Date" in Section 1.1 of the
Agreement is hereby modified, amended and restated to read in its entirety as
follows:

"Commitment Termination Date: February 6, 2002 or such later date to which the
Commitment Termination Date may be extended (if extended) in the sole discretion
of the Purchasers in accordance with the terms of Section 2.3(b)."

(2)The following definition is hereby added in its entirety to Section 1.1 of
the Agreement:

"Third Amendment Date: The date on which the Third Amendment to the Agreement
shall become effective."

(c)The first sentence of Section 2.1 of the Agreement is hereby amended and
restated to read in its entirety as follows:

"On the basis of the representations and warranties and subject to the terms and
conditions herein set forth, the Issuer agrees to deliver to the Deal Agent on
behalf of the Purchasers on the Third Amendment Date, the Class A Note with a
maximum principal amount of $180,000,000, which Class A Note shall be duly
executed by the Issuer, duly authenticated by the Indenture Trustee and
registered in the name of the Deal Agent on behalf of the Purchasers."

    SECTION 2.  Agreement in Full Force and Effect as Amended.  Except as
specifically amended hereby, the Agreement shall remain in full force and
effect. All references to the agreement shall not constitute a novation of the
Agreement, but shall constitute an amendment thereof. The parties hereto agree
to be bound by the terms and conditions of the Agreement, as amended by this
Third Amendment, as though such terms and conditions were set forth herein.

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    SECTION 3.  Miscellaneous.  

    (a) This Third Amendment may be executed in any number of counterparts, and
by the different parties hereto on the same or separate counterparts, each of
which shall be deemed to be an original instrument but all of which together
shall constitute one and the same agreement.

    (b) The descriptive headings of the various sections of this Third Amendment
are inserted for convenience of reference only and shall not be deemed to affect
the meaning or construction of any of the provisions hereof.

    (c) This Third Amendment may not be amended or otherwise modified except as
provided in the Agreement.

    (d) THIS THIRD AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES UNDER
THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REFERENCE TO ITS CONFLICT OF LAWS
PROVISIONS.

[Remainder of Page Intentionally left Blank]

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    IN WITNESS WHEREOF, the parties have caused this Third Amendment to the
Agreement to be executed by their respective officers thereunto duly authorized
as, of the date first above written.

THE ISSUER:   WLFC FUNDING CORPORATION
 
 
By:
 
/s/ NICHOLAS J. NOVASIC   

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    Title:   Chief Financial Officer
THE SERVICER:
 
WILLIS LEASE FINANCE CORPORATION
 
 
By:
 
/s/ NICHOLAS J. NOVASIC   

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    Title:   Chief Financial Officer
THE INVESTOR:
 
FIRST UNION NATIONAL BANK
 
 
By:
 
/s/ BILL A. SHIRLEY   

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    Title:   Senior Vice President
 
 
 
 
First Union National Bank
One First Union Center, TW-9
Charlotte, North Carolina 28288
Attention: Credit Administration
Facsimile No.: (704) 374-6355
Confirmation No.: (704) 374-4001
VFCC:
 
VARIABLE FUNDING CAPITAL CORPORATION
 
 
By:
 
FIRST UNION SECURITIES, INC.,
as attorney-in-fact
 
 
By:
 
DOUGLAS R. WILSON, SR.

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    Title:   Vice President
 
 
 
 
Variable Funding Capital Corporation
c/o First Union Securities, Inc.
One First Union Center, TW-9
Attention: Conduit Administration
Facsimile No.: (704) 383-6036
Confirmation No.: (704) 383-9343

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                        with a copy to:
 
 
 
Lord Securities Corp.
2 Wall Street, 19th Floor
New York, New York
Attention: Vice President
Facsimile No.: (212) 346-9012
Confirmation No.: (212) 346-9008
THE DEAL AGENT:
 
FIRST UNION SECURITIES, INC.
 
 
By:
 
/s/ LEAH W. FORSTNER   

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    Title:   Director
 
 
 
 
First Union Securities, Inc.
One First Union Center, TW-9
Charlotte, North Carolina 28288
Attention: Conduit Administration
Facsimile No.: (704) 383-6036
Telephone No.: (704) 383-9343
THE LIQUIDITY AGENT:
 
FIRST UNION NATIONAL BANK
 
 
By:
 
/s/ BILL A. SHIRLEY   

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    Title:   Senior Vice President
 
 
 
 
First Union National Bank
One First Union Center, TW-9
Charlotte, North Carolina 28288
Attention; Credit Administration
Facsimile No.: (704) 374-6355
Telephone No.: (704) 374-4001

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THIRD AMENDMENT TO NOTE PURCHASE AGREEMENT