The North American Aviation P-51 Mustang was a long-range single-seat fighter aircraft that entered service with Allied air forces in the middle years of World War II. The P-51 flew most of its wartime missions as a bomber escort in raids over Germany, helping ensure Allied air superiority from early 1944. It also saw limited service against the Japanese in the Pacific War. The Mustang began the Korean War as the United Nations' main fighter, but was relegated to a ground attack role when superseded by jet fighters early in the conflict. Nevertheless, it remained in service with some air forces until the early 1980s.