Northorp YF-17 Cobra ( F/A-18 A Hornett ancestor )

In 1972, the USAF sought proposals for a new fighter under the Lightweight Fighter (LWF) program. The LWF prototype program called for a small, lightweight, low cost, air superiority day fighter designed for high performance and ease of maintenance. The Northrop YF-17 was tested against the General Dynamics YF-16 in the LWF fly-off competition. The F-16 won and entered production starting in 1975.

The US Navy also evaluated the YF-17 and was interested in developing a strengthened version capable of carrier operation. Northrop teamed with McDonnell Douglas to develop this new air combat fighter which evolved into the F-18.

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a reply to: ultra_phoenix
This thread may be 20 years old, but why did the USAF select the F-16 over the YF-17 as the winner of the LWF competition?

a reply to: Potlatch

Because the F-16 met all their requirements, out flew the YF-17, except in a narrow window, and shared engine commonality with the F-15.