General Dynamics F-16 Fighting Falcon F-16XL

The F-16XL replaced the standard cropped-delta wing with a cranked-arrow delta wing that more than doubled wing area (58.8 m² versus roughly 27.9 m² on a standard F-16), lengthened the fuselage, and added internal fuel and payload capacity. It lost to the F-15E in the USAF's 1984 Enhanced Tactical Fighter competition. Two prototypes were built (a single-seat XL-1 and a two-seat XL-2, the latter fitted with a General Electric F110 engine), which NASA used from 1988 onward to study supersonic laminar flow and boundary-layer control on delta wings.