PROMISSORY NOTE

$600,000                                                          August 5, 1999

     FOR  VALUE  RECEIVED,   COMPUFLIGHT,  INC.,  a  Delaware  corporation  (the
"Maker"),  with its  principal  place of business at 175  Columbia  Street West,
Waterloo,  Ontario Canada,  promises to pay to the order of RUSSELL K. THAL (the
"Payee"), with an address at 26 Ridge Drive, Port Washington, New York 11050, or
at such other  place as the holder  hereof  may from time to time  designate  in
writing,  the principal sum of SIX HUNDRED THOUSAND DOLLARS ($600,000),  without
interest,  in  ninety-six  (96) equal  installments  of SIX THOUSAND TWO HUNDRED
FIFTY DOLLARS ($6,250),  payable on the tenth (10) and twenty-fifth  (25th) days
of each month beginning November 25, 1999 and ending November 10, 2003 ("Note").
Notwithstanding  the foregoing,  the Maker shall be entitled to deduct from each
payment due hereunder all applicable withholding taxes.

     This Note is given pursuant and subject to the terms and conditions of that
certain Retirement Agreement of even date between the Maker and the Payee.

     If any of the following  events or conditions shall happen or occur (in any
case, an "Event of Default"): (i) a default by the Maker in the due and punctual
payment of any amount due hereunder and the continuance  thereof for a period of
fifteen (15) days following receipt of written notice of default from the Payee;
(ii) the  application  by the  Maker  for,  or  consent  by the  Maker  to,  the
appointment  of a receiver,  trustee or liquidator of itself or of its property;
(iii) a general  assignment by the Maker for the benefit of creditors;  (iv) the
filing by the Maker of a voluntary  petition in  bankruptcy  or a petition or an
answer seeking reorganization or an arrangement with creditors; or (v) the Maker
having an  involuntary  petition  in  bankruptcy  filed  against it which is not
dismissed,  discharged  or stayed  within sixty (60) days,  then and in each and
every such Event of  Default,  the Payee  may,  by written  notice to the Maker,
declare the entire unpaid amount of this Note then  outstanding  to be forthwith
due and payable whereupon the same shall become forthwith due and payable.

     This Note may not be waived,  changed,  modified or discharged  orally, but
only by an agreement in writing, signed by the party against whom enforcement of
any waiver, change, modification or discharge is sought.

     Should  this Note be placed in the hands of any  attorneys  for  collection
upon the occurrence of an Event of Default, the Maker agrees to pay, in addition
to all other  amounts  due and  payable  hereunder,  all costs and  expenses  of
collection, including reasonable attorneys' fees.

     Except as  provided  for above,  the Maker  expressly  waives  presentment,
demand, protest, notice of dishonor,  notice of maturity, notice of protest, and
diligence in collection.


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     Any notice, demand or request relating to any matter set forth herein shall
be in writing and shall be deemed effective when hand delivered,  or one (1) day
following the date mailed by overnight mail or nationally  recognized  overnight
courier  to the  Maker  or the  Payee at its  address  stated  herein  (provided
confirmation  of receipt is obtained) or at such other address of which it or he
shall have notified the party giving such notice in writing as aforesaid.

     This Note may be prepaid in whole or in part without premium or penalty.

     This Note shall be governed by, and interpreted and construed in accordance
with,  the laws of the State of New  York,  excluding  choice of law  principles
thereof.

     The Maker  hereby  agrees  that any legal  action  with regard to this Note
shall be brought in the courts of the State of New York or of the United  States
of America for the Eastern  District of New York and hereby  appoints  Certilman
Balin  Adler & Hyman,  LLP,  90 Merrick  Avenue,  East  Meadow,  New York 11554,
Attention: Fred Skolnik, Esq., as its agent for service of process in connection
therewith.




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     IN WITNESS WHEREOF,  the Maker has duly executed this Promissory Note as of
the day and year first above written.

                                                              COMPUFLIGHT, INC.

                                                      By:/s/ Duncan Macdonald
                                                         -----------------------
                                                         Duncan Macdonald
                                                         Chief Executive Officer