Boeing built two Model 953 prototypes for the YC-14 Short Takeoff and Landing (STOL) aircraft, which introduced several significant technological breakthroughs. The Boeing YC-14 benefited from earlier "powered lift" studies, and included both externally-blown flaps as well as upper-surface blowing (USB). In the YC-14 USB system, the engine is placed over the top surface of the wing, blowing over the flaps. USB is a fairly rare concept in use and has been incorporated on just a few other aircraft.

The YC-14 prototypes were returned to Boeing at the completion of flight testing in the late summer of 1977.