F-16XL General DynamicsF 16XL USAF concept fighter plane airplane model. The F 16XL aircraft were built by General Dynamics as prototypes for a derivative fighter evaluation program conducted by the Air Force between 1982 and 1985. The aircraft were developed from basic F 16 airframes, with the most notable difference is the delta (cranked arrow) wing which give the aircraft a greater range because of increased fuel capacity in the wing tanks, and a larger load capability