Facing changed circumstances in relations with the Soviet Union and in US satellite development, US policymakers and intelligence officials had to come to grips with how best to use the A-12 as it neared completion. Its intended purpose, replacing the U-2 in overflights of the Soviet Union, had become less and less likely well before the A-12 was operational. Soviet air defenses had advanced to the point that even an aircraft flying faster than a rifle bullet at the edge of space could be tracked. In any event, President Kennedy had stated publicly that the United States would not resume such missions.

The A-12’s unique design and characteristics became the foundation for three other versions of supersonic aircraft that Lockheed built for CIA and the Air Force: the YF-12A, the M-21, and the SR-71.