Second F-15EX Fighter Jet Deployed at Eglin Air Force Base for Testing 1 May 2021, 7:16 UTC · by 15 photos This second airplane is part of a small fleet of eight expected to be delivered to the U.S. Air Force (USAF) this year, and part of a large, 200-units strong Indefinite Delivery/Indefinite Quantity contract assigned to Boeing by the military branch in July last year. The F-15EX represents a major evolution of one of America’s most famous and long-lived fighter jets. The version has been in the works for a while, and when it soared to the sky in the hands of the Eglin pilots, it became the first new F-15 variant to do that in 15 years.