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 service against the Japanese in the Pacific War. The Mustang began the Korean War as the United Nations' main fighter but was supplanted as a fighter by jets early in the conflict, being relegated to a ground attack role. Nevertheless, it remained in service with some air forces until the early 1980s.

Despite being economical to produce, the Mustang was a well-made and rugged aircraft. The definitive version of the single-seat fighter was powered by the Packard V-1650-3, a two-stage two-speed supercharged 12-cylinder Packard-built version of the legendary Rolls-Royce Merlin engine, and armed with six aircraft versions of the .50 caliber (12.7 mm) Browning machine guns. Like most other fighters that used a liquid-cooled engine, its weakness was a coolant system that could be punctured by a single bullet.