<PAGE>
                                                                   Exhibit 10.37

                               FLEET NATIONAL BANK
                               100 Federal Street
                           Boston, Massachusetts 02110

                                  June 27, 2002

Mercury Air Group, Inc.
5456 McConnell Avenue
Los Angeles, California 90066
Attention: Robert Schlax, Chief Financial Officer

      Re: Limited Waiver and Consent regarding Sale

Dear Mr. Schlax:

      Reference is hereby made to that certain Revolving Credit and Term Loan
Agreement dated as of March 2, 1999 (as amended, modified, supplemented or
restated and in effect from time to time, the "Credit Agreement") by and among
(a) Mercury Air Group, Inc., a Delaware corporation having its principal place
of business at 5456 McConnell Avenue, Los Angeles, California 90066 (the
"Borrower"), (b) Fleet National Bank (f/k/a BankBoston, N.A.), a national
banking association, as agent (in such capacity, the "Agent") for itself and the
other Banks referred to below, and (c) Fleet National Bank and the other
financial institutions from time to time parties thereto (collectively, the
"Banks"). Capitalized terms used in this letter agreement shall have the
respective meanings assigned to such terms in the Credit Agreement, unless
otherwise defined in this letter agreement.

      The Borrower has notified the Agent that it has entered into an Asset
Purchase Agreement (the "Asset Purchase Agreement") dated June 27, 2002 with
Signature Flight Support Corporation ("Signature Flight"), a Delaware
corporation. Pursuant to the terms of the Asset Purchase Agreement, the Borrower
has agreed to sell the "Purchased Assets" (as such term is defined in the Asset
Purchase Agreement) to Signature Flight for the minimum consideration of
$15,500,000 to be used by the Borrower as set forth in this letter agreement
(the "Sale Transaction"). The Borrower has requested that the Agent and the
Banks consent to the Sale Transaction as contemplated by the Asset Purchase
Agreement and waive any defaults which may otherwise be occasioned thereby, to
the limited extent necessary to allow the Sale Transaction. The Agent and the
Banks have agreed to do so, but only upon the terms and conditions contained in
this letter agreement.

      1.    Subject to the terms and conditions contained herein, and upon the
            satisfaction of each of the conditions set forth below, and to the
            extent required by the terms of the Credit Agreement, the Agent and
            each of the Banks hereby consent to the Sale Transaction as
            contemplated by the terms and conditions of the Asset Purchase
            Agreement and waive any defaults which may otherwise be occasioned
            thereby, to the limited extent necessary to allow the Sale
            Transaction.

      2.    The limited consent and waivers set forth in this letter agreement
            shall not be effective until the complete satisfaction of each of
            the following conditions, each in form and substance satisfactory to
            the Agent:

            (a)   The Agent's receipt of five (5) original counterpart signature
                  pages to this letter


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                  agreement, duly executed and delivered by the Banks, the
                  Borrower and each of the Guarantors;

            (b)   The Agent's receipt from the Borrower of Net Proceeds (as
                  defined below) from the Sale Transaction in the minimum amount
                  of $15,050,000 to be applied in reduction of the Obligations
                  as set forth in this letter agreement; and

            (c)   The Borrower shall have executed and delivered to the Agent
                  copies, certified by an officer of the Borrower as true,
                  correct and complete copies, of the Asset Purchase Agreement
                  and all other documents executed by either the Borrower and/or
                  Signature Flight in connection with the Sale Transaction.

      3.    The Borrower hereby covenants and agrees as follows:

            (a)   That the Borrower shall cause Signature Flight to remit the
                  proceeds from the Sale Transaction, net of closing costs and
                  expenses as set forth on the Sources and Uses Schedule
                  attached hereto as EXHIBIT "A" (the "Net Proceeds"), directly
                  to the Agent using the wire transfer instructions set forth on
                  EXHIBIT "B" attached hereto;

            (b)   The Borrower hereby instructs the Agent to apply the Net
                  Proceeds as follows:

                  (i)   The amount of $11,520,000 of the Net Proceeds shall be
                        applied by the Agent in prepayment of the Acquisition
                        Loans. The Borrower hereby confirms that, in accordance
                        with Section 6.1 of the Credit Agreement, such
                        prepayment shall be a permanent payment and shall not be
                        available for reborrowing, and the Total Acquisition
                        Loan Commitment shall be automatically reduced by the
                        amount of such prepayment.

                  (ii)  The remaining amount of the Net Proceeds (namely,
                        $3,530,000, which amount shall be referred to as the
                        "Remaining Net Proceeds") shall be held by the Agent as
                        additional cash Collateral. After such time as the
                        Borrower has established a demand deposit account (the
                        "DDA") with the Agent, which the Borrower shall
                        establish by no later than July 3, 2002, the Agent shall
                        deposit the Remaining Net Proceeds into the DDA.
                        Further, to secure the prompt, punctual, and faithful
                        performance of all and each of the Obligations, the
                        Borrower hereby grants to the Agent, for the ratable
                        benefit of the Banks and the Agent, a security interest
                        in and to, and assigns, pledges, and delivers to the
                        Agent, for the ratable benefit of the Banks and the
                        Agent, the DDA and any and all replacements, additions,
                        and substitutions thereto, and all funds, products,
                        proceeds, substitutions, additions, income (including,
                        without limitation, all interest), and other
                        distributions in respect thereto, and all books,
                        records, and papers relating to same (all of which is
                        referred to hereinafter as the "DDA Collateral"). The
                        Banks agree that the Borrower may withdraw all or a
                        portion of the DDA Collateral for the sole purpose of
                        satisfying any capital gains taxes which may become due
                        and owing by the Borrower as a result of the Sale
                        Transaction, provided, however, that the Borrower's
                        ability to withdraw


                                     Page 2
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                        any amounts from the DDA Collateral is expressly
                        conditioned upon each of the following:

                        (1)   No Default or Event of Default has occurred under
                              the Credit Agreement or any of the other Loan
                              Documents;

                        (2)   The Borrower has provided the Agent with a written
                              request to make a withdrawal from the DDA
                              Collateral, which written request shall contain a
                              detailed description of the capital gains taxes
                              which are due and payable, together with a
                              certification executed by the principal financial
                              or accounting officer of the Borrower that no
                              Default or Event of Default has occurred or is
                              continuing; and

                        (3)   The Borrower has provided the Agent with evidence,
                              in form and substance satisfactory to the Agent,
                              in its sole discretion, supporting the written
                              request referred to in clause (2) above.

                  (iii) Notwithstanding anything to the contrary contained in
                        clause (ii) above, in the event that the Borrower fails
                        to establish the DDA as required by the terms of clause
                        (ii) above, then the Agent shall have the right, in its
                        sole discretion, to apply the Remaining Net Proceeds in
                        reduction of the Acquisition Loans, as set forth in
                        clause (i) above.

            (c)   Within three (3) Business Days from the date of this letter
                  agreement, the Borrower shall execute and deliver to the Agent
                  a pledge and security agreement (the "DDA Pledge Agreement")
                  in favor of the Agent, for the ratable benefit of the Banks
                  and the Agent, to confirm the pledge and grant of a security
                  interest in and to the DDA Collateral. The DDA Pledge
                  Agreement shall be in form and substance satisfactory to the
                  Agent in its sole discretion.

            (d)   The Borrower acknowledges and agrees that this letter
                  agreement is being entered into by the Agent and the Banks in
                  reliance upon the terms of the Asset Purchase Agreement
                  previously delivered to the Agent by the Borrower, a copy of
                  which is attached hereto as EXHIBIT "C". Accordingly, the
                  Borrower covenants and agrees that the Borrower shall not
                  modify, amend or waive any term or condition of the Asset
                  Purchase Agreement without the prior written consent of the
                  Agent.

      4.    The Borrower hereby acknowledges and agrees that the failure of the
            Borrower to comply with any of the covenants and agreements of the
            Borrower contained in this letter agreement shall constitute and
            immediate Event of Default under the terms of the Credit Agreement.

      5.    The Borrower hereby acknowledges and agrees that nothing contained
            herein shall be deemed to constitute a representation or warranty of
            the Agent and/or the Banks that any of the representations,
            warranties, covenants and agreements of the Borrower contained in
            the Asset Purchase Agreement are true and accurate or will or can be
            fulfilled by the Borrower.

      6.    The Agent and the Banks agree that upon the Agent's determination
            that each of the conditions to the effectiveness of this letter
            agreement (as set forth in Paragraph 2, above)


                                     Page 3
<PAGE>

            have been satisfied, all liens and encumbrances which the Agent and
            the Banks may have in and to the Purchased Assets shall be released
            and terminated and, at the Borrower's sole cost and expense, the
            Agent shall deliver such UCC-3 Amendments and other documents as may
            be reasonably requested by the Borrower necessary to evidence such
            release and termination.

      7.    The limited waivers and consent contained in this letter agreement
            are limited strictly to their respective terms, shall apply only to
            the specific matters and events described herein, shall not extend
            to or affect any of the Borrower's or the Guarantors' other
            obligations contained in the Credit Agreement or any other Loan
            Document. Except as expressly set forth herein, nothing contained
            herein shall be deemed to be a waiver of, or shall in any way impair
            or prejudice, any rights of the Agent or the Banks under the Credit
            Agreement or any other Loan Document. Nothing contained herein shall
            be construed as a willingness on the part of the Agent and the Banks
            to grant any similar or other future consent or limited waivers.

      8.    The Borrower and the Guarantors each acknowledge and agree that (i)
            neither the Borrower nor the Guarantors have any claim or cause of
            action of any kind against any of the Banks or the Agent (or any of
            their respective directors, officers, employees, agents or
            affiliates); (ii) neither the Borrower nor the Guarantors have any
            offset right, counterclaim or defense of any kind against any of
            their respective obligations, indebtedness or liabilities owed to
            any of the Banks or the Agent; and (iii) each of the Banks and the
            Agent have heretofore performed and satisfied in a timely manner all
            of their obligations to either the Borrower and/or the Guarantors.
            In order to eliminate any possibility that any past conditions,
            acts, omissions, events, circumstances or matters would impair or
            otherwise adversely affect any of the Banks' or the Agent's rights,
            interests, contracts, collateral security or remedies, the Borrower
            and the Guarantors each hereby unconditionally release, waive and
            forever discharge (A) any and all liabilities, obligations, duties,
            promises or indebtedness of any kind of any of the Banks or the
            Agent to either of them, and (B) all claims, offsets, causes of
            action, suits or defenses of any kind whatsoever (if any), whether
            known or unknown, which either of them might otherwise have against
            any of the Banks or the Agent or any of their respective directors,
            officers, employees, agents or affiliates for their respective
            actions or omissions occurring prior to the date hereof, in either
            case (A) or (B) above, on account of any condition, act, omission,
            event, contract, liability, obligation, indebtedness, claim, cause
            of action, defense, circumstance or matter of any kind whatsoever
            which existed, arose or occurred at any time prior to the date
            hereof.

      9.    This letter agreement may be executed in any number of counterparts,
            each of which when so executed shall be deemed to be an original and
            all of which taken together shall constitute one and the same
            instrument. THIS LETTER AGREEMENT SHALL BE AN INSTRUMENT UNDER SEAL
            AND SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS
            OF THE COMMONWEALTH OF MASSACHUSETTS (WITHOUT REFERENCE TO
            PRINCIPLES OF CONFLICTS OR CHOICE OF LAW).


                                     Page 4
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      Kindly acknowledge the Borrower's and the Guarantors' agreement with the
terms and conditions of this letter agreement by signing where indicated below
and returning five (5) original counterpart signatures pages of this letter
agreement to the Agent.

                                             FLEET NATIONAL BANK
                                             (f/k/a BankBoston, N.A.),
                                             as Agent and as a Bank

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

                                             UNITED CALIFORNIA BANK
                                             (f/k/a Sanwa Bank California)

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

                                             GE CAPITAL CFE, INC.

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

                                             UNION BANK OF CALIFORNIA, N.A.

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

Accepted and Agreed to by the Borrower
and the Guarantors:

MERCURY AIR GROUP, INC.


By:
    -----------------------
Name:
Title:

MAYTAG AIRCRAFT CORPORATION


By:
    -----------------------
Name:
Title:

MERCURY AIR CARGO, INC.


                                     Page 5
<PAGE>

By:
    -----------------------
Name:
Title:

MERCURY ACCEPTANCE CORPORATION


By:
    -----------------------
Name:
Title:

EXCEL CARGO, INC.


By:
    -----------------------
Name:
Title:

MERCURY AIR CENTERS, INC.
(f/k/a Wofford Flying Service, Inc.)


By:
    -----------------------
Name:
Title:

AEG FINANCE CORPORATION


By:
    -----------------------
Name:
Title:

JUPITER AIRLINE AUTOMATION SERVICES, INC.
(f/k/a RPA Airline Automation Services, Inc. and
Rene Perez and Associates, Inc.)


By:
    -----------------------
Name:
Title:

HERMES AVIATION, INC.


                                     Page 6
<PAGE>

By:
    -----------------------
Name:
Title:

VULCAN AVIATION, INC.


By:
    -----------------------
Name:
Title:

MERCFUEL, INC.


By:
    -----------------------
Name:
Title:


                                     Page 7
<PAGE>

                                   EXHIBIT "A"

                             MERCURY AIR GROUP, INC.
                                BEDFORD FBO SALE
                           SOURCES AND USES STATEMENT
                           ESTIMATED AS JUNE 28, 2002
                      (all amounts in thousands of dollars)

                                SOURCES AND USES
--------------------------------------------------------------------------------

<TABLE>
<S>                     <C>             <C>                             <C>
Source of Funds                         Uses of Funds
   Bedford FBO Sale     15,500             Bedford Closing Costs             0
                                           Hold Back Escrow                250
                                           Massport Fee                    200
                                           Bedford Taxes                 3,530
                                           Fleet Debt Reduction         11,520
                        ------                                          ------
   Total Sources        15,500                Total Uses                15,500
                        ======                                          ======
</TABLE>


<PAGE>

                                   EXHIBIT "B"

                           WIRE TRANSFER INSTRUCTIONS

          ------------------------------------------------------
          ABA #:                   011000138
          BANK NAME:               FLEET NATIONAL BANK
          CITY:                    BOSTON
          STATE:                   MASSACHUSETTS
          ACCOUNT NUMBER:          151035241515
          ACCOUNT NAME:            AGENCY SERVICES WIRE SUSPENSE
          REF:                     MERCURY AIR GROUP 31073133
          ATTENTION:               AGENCY SERVICES - NEW YORK
          ------------------------------------------------------