Sabreliner 65Rockwell Sabreliner 65 airplane model. The Sabreliner was successfully developed for both military and civil use. North American Aviation began work on the Sabreliner as a private venture but it was formally launched in August 1956 in response to the US Air Force's UTX (Utility Trainer Experimental) requirement for a utility jet aircraft capable of performing transport and combat readiness training missions. A civil configured prototype (designated