Lockheed's previous reconnaissance aircraft was the relatively slow U-2, designed for the Central Intelligence Agency (CIA). As of 2023 the SR-71 holds the world record, which it set in 1976, as the fastest air-breathing manned aircraft, previously held by the related Lockheed YF-12. Since its retirement, the SR-71's role has been taken up by a combination of reconnaissance satellites and unmanned aerial vehicles (UAVs) a proposed UAV successor, the SR-72, is under development by Lockheed Martin, and scheduled to fly in 2025. A total of 32 aircraft were built 12 were lost in accidents with none lost to enemy action. On average, each SR-71 could fly once per week due to the extended turnaround required after mission recovery. If a surface-to-air missile launch was detected, the standard evasive action was simply to accelerate and outpace the missile. During missions, the SR-71 operated at high speeds and altitudes (Mach 3.2 and 85,000 feet, 25,900 meters), allowing it to outrace or entirely avoid threats. Mission equipment for the plane's aerial reconnaissance role included signals intelligence sensors, side looking airborne radar, and a camera. NASA was the final operator of the Blackbird, using it as a research platform it was retired again in 1999. In 1989, the USAF retired the SR-71, largely for political reasons several were briefly reactivated during the 1990s before their second retirement in 1998. The SR-71's existence was revealed to the public in July 1964 it entered service in the United States Air Force (USAF) in January 1966.

The SR-71 was longer and heavier than the A-12, allowing it to hold more fuel as well as a two-seat cockpit. Initially, a bomber variant of the A-12 was requested by Curtis LeMay, before the program was focused solely on reconnaissance. The shape of the SR-71 was based on that of the Lockheed A-12, which was one of the first aircraft to be designed with a reduced radar cross-section. American aerospace engineer Clarence 'Kelly' Johnson was responsible for many of the aircraft's innovative concepts. The SR-71 was developed as a black project from the Lockheed A-12 reconnaissance aircraft during the 1960s by Lockheed's Skunk Works division. The SR-71 has several nicknames, including ' Blackbird' and ' Habu'. The Lockheed SR-71 ' Blackbird' is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporation.

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