President Lyndon Johnson presents the Harmon International Aviator's Trophy to Major William J. Knight for his X-15A-2 flight to 4,520 mph (Mach 6.7) on October 3, 1967. This was the highest speed reached in the joint Air Force/NASA X-15 program. The experience gained with the X-15 and the lifting body programs would be used in designing the space shuttle. NASA Photo ECN-1025
