DARPA began working with the U.K. Ministry of Defense (MoD) to develop a follow-on supersonic generation to the AV-8 Harrier, a pioneer aircraft for short takeoff and landing (STOL) capabilities. The international program that emerged from this intention, the Advanced Short Takeoff Vertical Landing (ASTOVL), expired in 1991, but various component efforts toward the same end continued.
DARPA worked with the U.S. Navy to establish a development program for an STOVL Strike Fighter with capabilities specified by the Navy in 1988. The program evolved toward an aircraft that could build on much of the design base for the Air Force F-16.
