The Lockheed YF-12 was an American prototype interceptor aircraft, which the United States Air Force evaluated as a development of the highly-secret Lockheed A-12 that also spawned the now famous SR-71 Blackbird.[1]. The YF-12 is frequently called the Blackbird by players, which is accurate, considering the YF-12 is essentially an SR-71 with no survailence gear and air-to-air weaponry.