The McDonnell Douglas F-15 Eagle is an American twin-engine, all-weather tactical fighter aircraft designed by McDonnell Douglas. Following reviews of proposals, the United States Air Force (USAF) selected McDonnell Douglas's design in 1969 to meet the service's need for a dedicated air superiority fighter. The Eagle first flew in July 1972, and entered service in 1976. It is among the most successful modern fighters, with over 100 victories and no losses in aerial combat, with the majority of the kills by the Israeli Air Force.

A twinjet or twin-engine jet is a jet aircraft powered by two engines. A twinjet is able to fly well enough to land with a single working engine, making it safer than a single-engine aircraft in the event of failure of an engine. Fuel efficiency of a twinjet is better than that of aircraft with more engines. These considerations have led to the widespread use of aircraft of all types with twin engines, including airliners, fixed-wing military aircraft, and others.