THE EFFECT OF STRESS ON FIBRINOLYSIS WAS INVESTIGATED IN PILOTS BEING TRAINED IN THE STARFIGHTER. THE PHYSICAL STRESSES DUE TO ACCELERATIONS AND EMOTIONAL STRESSES DURING FLIGHT ARE DISCUSSED ALONG WITH THE TEST METHODS. AN AVERAGE INITIAL VALUE OF 192.3 MINUTES WAS FOUND FOR THE EUGLOBULIN-LYSIS TIME, AND THE AVERAGE DROP WAS 44 TO 56% FOR THE ENTIRE FLIGHT PROGRAM. THE SIGNIFIES AN IMPORTANT INTENSIFICATION OF FIBRINOLYTIC ACTIVITY, AS THE CLOT DURABILITY IS REDUCED BY HALF. IT IS RECOMMENDED THAT FIBRINOLYSIS INHIBITORS BE INCLUDED WITH BLOOD SUPPLIES FOR AIRCRAFT ACCIDENTS.