<PAGE>

EXHIBIT 10.9

                          Allonge to Promissory Note


     By this Allonge to Promissory Note (this "Allonge"), the undersigned,
SUMMIT AVIATION, agrees that the Promissory Note (the "Original Note") of the
undersigned, dated September 30, 1998, and payable to SPACE APPLICATIONS
CORPORATION (now, SM&A Corporation (East), successor in interest), is amended by
deleting the following sentence:

     FOR VALUE RECEIVED, the undersigned, SUMMIT AVIATION, INC., a California
     corporation ("Maker"), hereby promises to pay to the order of SPACE
     APPLICATIONS CORPORATION, a California corporation ("Holder"), at its
     office at 4695 MacArthur Boulevard, Eighth Floor, Newport Beach, CA  92660,
     Attention: Chief Financial Officer, or at such other place or to such other
     party or parties as the Holder of this Note may from time to time
     designate, the principal sum of ONE MILLION EIGHT HUNDRED THOUSAND DOLLARS
     ($1,800,000), together with interest on the unpaid principal balance from
     time to time outstanding at the rate of nine percent (9%) per annum.
     Amounts owing hereunder shall be paid in thirty (30) equal monthly payments
     of Thirty Thousand Dollars ($30,000) each, commencing October 31, 1998,
     with a final balloon payment of all outstanding principal and interest
     owing hereunder due and payable on March 31, 2001.

and substituting therefor the following sentence:

     FOR VALUE RECEIVED, the undersigned, SUMMIT AVIATION, INC., a California
     corporation ("Maker"), hereby promises to pay to the order of SM&A
     CORPORATION (EAST), a California corporation successor to SPACE
     APPLICATIONS CORPORATION, a California corporation ("Holder"), at its
     office at 4695 MacArthur Boulevard, Eighth Floor, Newport Beach, CA  92660,
     Attention: Chief Financial Officer, or at such other place or to such other
     party or parties as the Holder of this Note may from time to time
     designate, the principal sum of ONE MILLION EIGHT HUNDRED THOUSAND DOLLARS
     ($1,800,000), together with interest on the unpaid principal balance from
     time to time outstanding at a rate equal to the LIBOR-three month rate as
     such may be in effect from time to time and as published in the Western
     Edition of the Wall Street Journal.  Amounts owing hereunder shall be paid
     in thirty (30) equal monthly payments of Thirty Thousand Dollars ($30,000)
     each, commencing October 31,
<PAGE>

    1998, with a final balloon payment of all outstanding principal and interest
    owing hereunder due and payable on March 31, 2001.

    No further changes are intended hereby.


Date: June 1, 1999

                                        SUMMIT AVIATION, INC.

                                        /s/ STEVEN S. MYERS
                                        ----------------------------------
                                        Steven S. Myers, President


                                        SM&A CORPORATION (EAST)

                                        /s/ MICHAEL A. PIRAINO
                                        ----------------------------------
                                        Michael A. Piraino, President

                                       2.
<PAGE>

EXHIBIT 10.10

AMENDMENT NO. 1 TO COMMON STOCK PURCHASE AGREEMENT

     THIS AMENDMENT NO. 1 TO COMMON STOCK PURCHASE AGREEMENT is dated as of June
1, 1999 by and between SM&A CORPORATION (EAST) ("SMAE") as successor-in-interest
to SPACE APPLICATIONS CORPORATION, a California corporation ("SAC"), and SUMMIT
AVIATION, INC., a California corporation ("Purchaser').


                               R E C I T A L S:
                               - - - - - - - -

     A.   SAC and Purchaser entered into that certain Common Stock Purchase
Agreement (the "Original Agreement') as of September 30, 1998.

     B    SMAE, as successor to SAC, and Purchaser desire to amend the  original
Agreement as specifically set forth below:

          1.   Section 1(c)(ii) shall be amended to read in its entirety as
               follows:

               "(ii)  After six (6) months, but within eighteen (18) months of
                      the date first set forth above, Purchaser shall pay to
                      [SAC] SMAE an amount equal to twenty-five percent (25%) of
                      any Excess Proceeds;"

          2.   Change in Interest Rate of Promissory Note:

                      The interest rate payable pursuant to the Note as defined
               in the Original Agreement is hereby changed from nine percent
               (9%) per annum to the LIBOR-three month rate. There shall be
               executed an Allonge to the Note setting forth such amended
               interest rate.

          3.   Except as set forth above, no further changes are intended with
               respect to the Original Agreement.

                                       3.
<PAGE>

                                        SM&A CORPORATION (EAST)

                                        successor-in-interest to

                                        Space Applications Corporation,
                                        a California corporation


                                        By /s/ MICHAEL A. PIRAINO
                                           ---------------------------
                                               Its President



                                               SUMMIT AVIATION, INC.,
                                               a California corporation


                                               By /s/ STEVEN S. MYERS
                                                  -------------------

                                       4.