Lockheed YF-12A The YF-12A was the forerunner of the highly sophisticated SR-71 high-altitude strategic reconnaissance aircraft. Unlike the SR-71, the YF-12A never became operational, but during the test program, which ended in 1966, it set a speed record of 2,070.101 mph and an altitude record of 80,257.86 feet. Both records were set on May 1, 1965 by Col. Robert L. "Fox" Stephens (pilot) and Lt. Col. Daniel Andre.