The SR-71, also called the Blackbird or the Habu (after an Okinawan species of pit viper) is an advanced long range, strategic reconnaissance aircraft; originally developed as part of the Lockheed Skunk Works "Black Project" during the Cold War. A need to develop a new reconnaissance aircraft became apparent when the Air Force's previous long range aircraft, the U-2, had become exposed in 1960 as one had been shot down over the USSR. The SR-71 was designed to operate at such high altitudes and speeds that it could outrun any threat posed.
Through its entire service and still today, the SR-71 was the fastest, highest-flying manned aerial vehicle in existence, accelerating to speeds faster than any interceptor, surface to air or air to air missile of its era. As a result, the SR-71 was commissioned with the United States from 1964 to 1998, only 32 were manufactured, 12 were lost due to accidents, and none were lost due to enemy action. Today, only 2 remain in service, both retained by the NASA Dryden Flight Research center.
It's flattened, tapered design as well as it's specially designed surface material, were utilized to reflect radar away from its origination point, giving it a significantly smaller radar cross section. The engines were a specially shaped conical design to minimize heat signature and cesium was often added to the fuel to minimize the residual heat in the exhaust plumes. It is said by its pilots and ground crew that the higher its altitude, and faster it travels the more fuel efficient it becomes.