F-16 Fighting Falcon

Genesis of the successful F-16 fighter/attack aircraft lies in reaction to severe deficiencies in US fighter design revealed by the Vietnam War.
Following the success of the small, highly maneuverable F-86 day fighter in the Korean War, US fighter design changed to emphasize maximum speed, altitude, and radar capability at the expense of maneuverability, pilot vision, and other attributes needed for close combat. This trend reached its extremity in the McDonnell Douglas F-4 Phantom, which was the principal fighter for both the US Air Force and Navy during the latter part of the Vietnam War.

The F-4 was originally designed as an interceptor for defense of the fleet against air attack - a mission neither it nor any other jet has ever executed, because no US fleet has come under air attack since the beginning of the jet age. Be that as it may, the F-4 interceptor was designed to meet the fleet defense mission by using rapid climb to high altitude, high supersonic speed, and radar-guided missiles to shoot down threat aircraft at long distance.
Used as a fighter rather than as an interceptor in Vietnam, the F-4 was severely miscast. Against very inferior North Vietnamese pilots flying small, highly maneuverable MiG-21s, the air-to-air kill ratio sometimes dropped as low as 2 to 1, where it had been 13 to 1 in Korea. As the Vietnam War drew to a close, it was generally agreed that the F-4 had prohibitive deficiencies including: