**Exhibit
      2.4**





**SECOND
      AMENDMENT TO STOCK PURCHASE AGREEMENT**




THIS
      SECOND AMENDMENT TO STOCK PURCHASE AGREEMENT (this “ ***Amendment*** ”)
      is
      effective as of the 21st day of July, 2007, among Macquarie FBO Holdings LLC,
      a
      Delaware limited liability company (the “ ***Purchaser*** ”),
      Mercury Air Centers, Inc., a Delaware corporation (the “ ***Company*** ”)
      and
      Allied Capital Corporation, a Maryland corporation, as the Seller
      Representative.




WHEREAS,
      the Purchaser, the Company, Allied Capital Corporation, Directional Aviation
      Group, LLC, Kenneth C. Ricci, David Moore and Allied Capital Corporation, as
      Seller Representative, entered into that certain Stock Purchase Agreement dated
      April 16, 2007, as amended on June 12, 2007 (the “ ***MAC/Macquarie
      SPA*** ”);
      and




WHEREAS,
      the Purchaser, the Company and the Seller Representative desire to amend the
      MAC/Macquarie SPA in accordance with Section 9.5 of the MAC/Macquarie SPA to
      reflect the terms set forth herein.




NOW,
      THEREFORE, for valuable consideration, the receipt and sufficiency of which
      are
      hereby acknowledged, the parties hereto hereby agree as follows:




1. The
      Recitals set forth above are incorporated herein by this reference thereto
      as
      though fully set forth below. Capitalized terms used in this Amendment but
      not
      otherwise defined herein shall have the meanings assigned to such terms in
      the
      MAC/Macquarie SPA.




2. The
      Airport Estoppel for the Ft. Wayne, Indiana FBO is hereby deleted from the
      list
      of Required Authorities on the Airport Estoppel Schedule.




3. A
      new
      sentence is hereby added to the end of Section 1 of the Excluded Assets Schedule
      as follows:




“The
      Purchaser, the Sellers and the Company hereby acknowledge and agree that: (i)
      the maintenance business operated at the Ft. Wayne, Indiana FBO will not be
      an
      Excluded Asset; (ii) all assets related to the operation of the maintenance
      business at the Ft. Wayne, Indiana FBO will be owned as of the Closing by the
      Company and/or Mercury Air Center - Ft. Wayne, LLC including employees,
      contracts and personal property; and (iii) the Hangar Sublease Agreement between
      Mercury Air Center - Ft. Wayne, LLC and Mercury Air Services, LLC dated as
      of
      July 1, 2006 has been terminated pursuant to the Termination of Hangar Sublease
      Agreement dated as of July 21, 2007.”




4. Except
      as
      provided herein, all other terms and conditions of the MAC/Macquarie SPA shall
      remain unchanged and in full force and effect and Purchaser’s execution of this
      Amendment shall not constitute waiver of any breach of any of the
      representations and warranties of the Sellers or the Company set forth in the
      Agreement.




5. The
      parties hereto may execute this Amendment by facsimile transmission in two
      or
      more counterparts (no one of which need contain the signatures of all of the
      parties hereto), each of which shall be an original and all of which together
      shall constitute one and the same instrument.







IN
      WITNESS WHEREOF, the parties have executed and delivered this Amendment
      effective as of the date first above written.




WITNESS:
            MACQUARIE FBO HOLDINGS LLCBy:
                Macquarie Infrastructure Company Inc.
              d/b/a
                Macquarie Infrastructure Company (US),
              as
                Managing Member/s/
                Francis T. Joyce
              _________________________
            By:/s/
              Peter Stokes
              Name:PETER
                STOKES
              Title:CHIEF
                EXECUTIVE OFFICERMERCURY AIR CENTERS, INC.__________________________
            By:/s/
              Kenneth C. Ricci
              Name:KENNETH
                C. RICCI
              Title:CHIEF
                EXECUTIVE OFFICERALLIED
                CAPITAL CORPORATION,
              as
                the Seller Representative/s/
                Scott Somer
              __________________________
            By:/s/
              Mark F. Raterman
              Name:MARK
                F. RATERMAN
              Title:PRINCIPAL