The F-15 is an all-weather tactical fighter which first entered service with the United States Air Force in 1976. Early A/B models very rapidly proved their worth and since its introduction the Eagle has been considered a thoroughbred of the fighter world. Continued development led to the modern-day F-15C/Ds and solidified the type's reputation as one of the most successful fast jet air superiority platforms in history. Recognising further potential, McDonnell Douglas (now Boeing) expanded the design still further to produce the F-15E Strike Eagle which joined the USAF in 1989; optimised for the air-to-ground strike role it has mirrored the accomplishments of its earlier cousins and proved vital to US operations across the globe. The F-15 has achieved significant export success and in addition to the United States Air Force/Air National Guard it has also served with countries such as Israel, Japan, Saudi Arabia, Singapore and the Republic of Korea. Although new 'fifth generation' aircraft such as the F-22 Raptor and F-35 Lightning II are expected to replace types such as the F-15, the US plans to operate the aircraft well in to the next decade.