The Lockheed A-12 Oxcart was a highly classified, single-seat strategic reconnaissance aircraft developed by the Lockheed Corporation's Advanced Development Projects office, better known as Skunk Works. Designed under the leadership of Clarence "Kelly" Johnson, the A-12 was commissioned by the CIA in 1959 as a high-altitude successor to the U-2. The aircraft was engineered to redefine the limits of speed and reconnaissance, utilizing a mostly titanium airframe and a stealthy shape. To further evade ground-based radar, the aircraft was coated in a specialized paint designed to scatter radar signals.
The A-12 first flew on April 26, 1962, at Groom Lake (Area 51), Nevada. Propulsion was provided by two Pratt & Whitney J58 turbo ramjet engines. A defining technical feature of these engines was the inclusion of prominent shock cones at the front of the intakes; these cones created shock waves to slow incoming air, preventing the engines from extinguishing at supersonic speeds. These innovations allowed the A-12 to achieve a sustained speed of Mach 3.2 at an altitude of 90,000 feet, a performance envelope that the CIA notes has never been surpassed by any other piloted operational jet aircraft.
Although developed in secrecy, the A-12 saw limited operational use between 1963 and 1968. The only dedicated reconnaissance operation, codenamed BLACK SHIELD, occurred from May 1967 to May 1968. Based at Kadena Air Force Base in Okinawa, a detachment of three A-12s and six pilots flew 29 missions over East Asia. This included 24 missions over North Vietnam to identify surface-to-air missile (SAM) sites. The A-12's final mission took place in 1968 over North Korea following the seizure of the USS Pueblo, where it confirmed the location of the ship and its crew and verified that North Korea was not preparing a large-scale invasion of South Korea.
In total, 15 A-12 airframes were produced. By 1968, President Lyndon B. Johnson ordered the retirement of the A-12 to avoid maintaining two similar fleets, as the US Air Force was fielding the SR-71 Blackbird—a derivative of the A-12—and the CORONA satellite system had become operational. Today, several A-12s survive as static museum exhibits, including Article 131 at the Southern Museum of Flight, Article 122 at the Intrepid Sea, Air & Space Museum, and a production number eight aircraft at CIA Headquarters.