The Lockheed SR-71 was a twin-engine stealth reconnaissance aircraft (SR = Strategic Reconnaissance) developed by Skunk Works, the secretive Advanced Development Projects Unit of Lockheed Martin, for the CIA and was in service with the US Air Force from 1966 to 1998. Known as the Blackbird, the reconnaissance plane reached speeds of Mach 3 and above and altitudes of 24 km, flying faster and higher than any surface-to-air missile, which is why no aircraft was ever shot down during its reconnaissance missions over enemy territory. The high speeds, which required the special and very expensive JP-7 fuel, the highly complex stealth technology, and the simultaneously advanced satellite technology all worked against the program and led to its end in 1998. Of the 32 SR-71s produced, 12 were lost in accidents. The aircraft owned by the USAF at the end of the program were all handed over to museums. The SR-71 still holds various speed records. Model with 1,374 parts, 1 figure, printed blocks, and movable elements. Model dimensions (LxWxH): 37.5 x 33.5 x 12.5 cm