 The chief reasons given by the Secretary were the YF-16's lower operating costs, greater range, and maneuver performance that was "significantly better" than that of the YF-17, especially at supersonic speeds.Another advantage of the YF-16 – unlike the YF-17 – was its use of the Pratt & Whitney F100 turbofan engine, the same powerplant used by the F-15; such commonality would lower the cost of engines for both programs.Secretary McLucas announced that the USAF planned to order at least 650, possibly up to 1,400 production F-16s.