The North American Sabreliner, later sold as the Rockwell Sabreliner, is an American mid-sized business jet developed by North American Aviation. It was offered to the United States Air Force (USAF) in response to its Utility Trainer Experimental (UTX) program. It was named "Sabreliner" due to the similarity of the wing and tail to North American's F-86 Sabre jet fighter. Military variants, designated T-39 Sabreliner, were used by the USAF, United States Navy (USN), and United States Marine Corps (USMC) after the USAF placed an initial order in 1959. The Sabreliner was also developed into a commercial variant. Design and development North American Aviation began development of the Sabreliner as an in-house project, and in response to the UTX request for proposals, offered a military version to the USAF. UTX combined two different roles, personnel transport and combat readiness training, into the same aircraft. The civilian version prototype, which carried the model number NA-265, made its first flight on September 16, 1958. It was powered by two General Electric YJ85 turbojet engines. The type received its Federal Aviation Administration (FAA) type certificate in April 1963. The UTX candidate, designated the T-39A, was identical in configuration to the NA-265, but when the contract was awarded and the T-39A entered production, it was powered by two Pratt & Whitney JT12A-8 turbojet engines. The civilian production version, or Series 40, was slightly refined over the prototype, with more speed and a roomier cabin. North American then stretched the design by , providing greater cabin space, and marketed it as the Series 60, which was certificated in April 1967. The cabin was made taller for the Series 70 and General Electric CF700 turbofans were installed for the Series 75A (also branded as the Series 80). By 1973, North American had merged with Rockwell Standard under the name Rockwell International. In 1976 Rockwell contracted Raisbeck Engineering to redesign the wing of the Sabreliner series. The resulting Raisbeck Mark V wing was the first supercritical wing in service in the United States. The Mark V wing was combined with Garrett TFE731 turbofan engines, to create the Series 65. Sabreliner models 60 and 80 were retrofitted with the Mark V wing as the Series 60A (STC SA687NW) and Series 80A (STC SA847NW). Sabreliner production came to a close in 1981. The next year, Rockwell sold its Sabreliner division to a private equity firm which formed Sabreliner Corporation,