SIXTH AMENDMENT TO CREDIT AGREEMENT

EXHIBIT 10.3

SIXTH AMENDMENT TO CREDIT AGREEMENT

THIS SIXTH AMENDMENT TO CREDIT AGREEMENT (the “Sixth Amendment”) is made effective as of August 1, 2004, among PEMCO AVIATION GROUP, INC., a Delaware corporation, PEMCO AEROPLEX, INC., an Alabama corporation, PEMCO ENGINEERS, INC., a Delaware corporation, PEMCO WORLD AIR SERVICES, INC., a Delaware corporation, SPACE VECTOR CORPORATION, a Delaware corporation (collectively, the “Borrowers”), SOUTHTRUST BANK, an Alabama banking corporation, as Agent (the “Agent”), SOUTHTRUST BANK, an Alabama banking corporation, as a Lender, and COMPASS BANK, an Alabama banking corporation, as a Lender. Capitalized terms used herein but not defined shall have the meanings as set forth in the Credit Agreement, as amended (as hereinafter defined).

WHEREAS, pursuant to that certain Credit Agreement dated as of December 16, 2002, among Borrowers, Agent, and the other Lender Parties a party thereto (the “Credit Agreement”), Lenders made available, subject to the terms and conditions thereof, (i) the Revolving Loan of up to $20,000,000.00, (ii) the Swing Line Loan of up to $5,000,000.00, and (iii) the Term Loan of up to $5,000,000.00; and

WHEREAS, pursuant to that certain First Amendment to Credit Agreement dated as of May 22, 2003, among Borrowers, Agent, and the other Lender Parties a party thereto (the “First Amendment”), the Credit Agreement was amended in order to extend to Borrowers the Treasury Stock Loan in the amount of up to $5,000,000.00; and

WHEREAS, pursuant to that certain Second Amendment to Credit Agreement dated as of November 24, 2003, among Borrowers, Agent, and the other Lender Parties a party thereto (the “Second Amendment”), the Credit Agreement was amended in order to (i) temporarily increase the Swing Line Loan Commitment to up to $7,000,000.00, and (ii) temporarily increase the Revolving Loan Commitment to up to $22,000,000.00; and

WHEREAS, pursuant to that certain Third Amendment to Credit Agreement dated as of December 16, 2003, among Borrowers, Agent, and the other Lender Parties a party thereto (the “Third Amendment”), the Credit Agreement was amended in order to (i) increase the Swing Line Loan Commitment to up to $6,000,000.00, (ii) increase the Revolving Loan Commitment to up to $25,000,000.00, and (iii) extend the Revolving Loan Maturity Date from December 16, 2004 until December 16, 2005; and

WHEREAS, pursuant to that certain Fourth Amendment to Credit Agreement dated as of May 7, 2004, among Borrowers, Agent, and the other Lender Parties a party thereto (the “Fourth Amendment”), the Credit Agreement was amended in order to (i) temporarily increase the Revolving Loan Commitment to up to $27,000,000.00, and (ii) increase the Letter of Credit Commitment to up to $1,500,000.00; and

WHEREAS, pursuant to that certain Fifth Amendment to Credit Agreement dated as of May 22, 2004, among Borrowers, Agent, and the other Lender Parties a party thereto (the “Fifth Amendment”), the Credit Agreement was amended in order to, among other things, extend the Treasury Stock Loan Advancement Termination Date from May 22, 2004 to May 22, 2005 (the

Credit Agreement, as amended by the First Amendment, the Second Amendment, the Third Amendment, the Fourth Amendment and the Fifth Amendment, hereinafter referred to as the “Credit Agreement, as amended”); and

WHEREAS, Lender Parties and Borrowers have agreed to amend the Credit Agreement, as amended, in order to extend until December 31, 2004 the temporary increase of the Revolving Loan Commitment to up to $27,000,000.00, as more specifically hereinafter provided.

NOW, THEREFORE, in consideration of One Dollar ($1.00) and other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties agree that the Credit Agreement, as amended, is hereby amended as follows:

1. The Credit Agreement, as amended, is hereby amended by deleting the definition of “Revolving Loan Commitment”, and by substituting the following new definition in lieu thereof:

“Revolving Loan Commitment” means the commitment of the Revolving Loan Lenders, subject to the terms of this Agreement, to lend Borrowers up to (A) from August 1, 2004 to December 31, 2004, the lesser of (i) Twenty-Seven Million and 00/100 Dollars ($27,000,000.00), or (ii) the Borrowing Base, less the Available Amount of the Letters of Credit, less any outstanding Letter of Credit Advances; and (B) thereafter, the lesser of (i) Twenty-Five Million and 00/100 Dollars ($25,000,000.00), or (ii) the Borrowing Base, less the Available Amount of the Letters of Credit, less any outstanding Letter of Credit Advances.

2. As a condition to the effectiveness of this Sixth Amendment (a) Agent shall have received appropriate resolutions of Borrowers’ directors, in a form satisfactory to Agent, authorizing Borrowers to enter into this Sixth Amendment and any other documentation required by Agent in connection with this Sixth Amendment; (b) Agent shall have received a Bringdown and Incumbency Certificate of each Borrower, in a form satisfactory to Agent; (c) Borrowers shall have executed and delivered to Agent all further documents and performed all other acts which Agent reasonably deems necessary or appropriate to perfect or protect its security for the Loans; and (d) Borrowers shall have delivered to Agent such other documentation, if any, as may be requested by Agent to satisfy Agent that this Sixth Amendment, and all other documents and instruments executed by Borrowers in connection with this Sixth Amendment or in furtherance hereof have each been duly authorized, executed and delivered on behalf of Borrowers, and constitute valid and binding obligations of Borrowers.

3. Each Borrower represents and warrants to Lender Parties that all representations and warranties given by such Borrower in Article IX of the Credit Agreement, as amended, are true and correct as of the date of this Sixth Amendment, except to the extent affected by this Sixth Amendment. Each Borrower represents and warrants to Lender Parties that as of the date of this Sixth Amendment, such Borrower is in full compliance with all of the covenants of such Borrower contained in Article X of the Credit Agreement, as amended, except to the extent affected by this Sixth Amendment.

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4. Except as heretofore or herein expressly modified, or as may otherwise be inconsistent with the terms of this Sixth Amendment (in which case the terms and conditions of this Sixth Amendment shall govern), all terms of the Credit Agreement, as amended, and all documents and instruments executed and delivered in furtherance thereof shall be and remain in full force and effect, and the same are hereby ratified and confirmed in all respects.

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IN WITNESS WHEREOF, this Sixth Amendment has been duly executed as of the day and year first above written.

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