PROMISSORY NOTE

US$134,700                                                         July 15, 1998

         FOR  VALUE  RECEIVED,   NAVTECH  APPLIED   RESEARCH  INC.,  an  Ontario
corporation (the "Maker"),  with its principal place of business at 175 Columbia
Street  West,  Waterloo,  Ontario,  Canada,  promises  to pay to  the  order  of
COMPUFLIGHT,  INC., a Delaware  corporation  (the  "Payee"),  with its principal
place of business at 175 Columbia Street West, Waterloo,  Ontario, Canada, or at
such  other  place as the  holder  hereof  may from  time to time  designate  in
writing,  the principal sum of ONE HUNDRED THIRTY FOUR THOUSAND SEVEN HUNDRED US
DOLLARS (US$134,700),  bearing 10% interest calculated using the 360 Day Method,
in thirty-six  (36) equal  installments  of FOUR THOUSAND THREE HUNDRED  SEVENTY
FIVE US DOLLARS AND TWENTY FIVE CENTS (US$4,375.25),  is payable on the last day
of the month  beginning  July 31,  1998,  and ending on June 30, 2000  ("Note").
Notwithstanding  the foregoing,  the Maker shall be entitled to deduct from each
payment due hereunder all applicable withholding taxes.

The Maker  agrees  that the  Royalty  Payments  defined in the  Navtech  Applied
Research Inc. Software License Agreement to be entered into no later than August
1, 1998 ("License  Agreement") may be applied,  in whole or in part, against any
outstanding principle amounts at the discretion of 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.

         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 Province of Ontario,  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  Province of Ontario  and hereby  appoints
Frank R. Volpini,  M.A., LL.B., 375 University Avenue East,  Waterloo,  Ontario,
N2K 3M7, as its agent for service of process in connection therewith.



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

                                                   NAVTECH APPLIED RESEARCH INC.

                                                          /s/    Dorothy English
                                                          ----------------------
                                                          By:
                                                          Dorothy English