The Grumman F4F Wildcat was an American carrier-based fighter aircraft that began service with both the United States Navy and the British Royal Navy (as the Martlet) in 1940. Although first used in combat by the British in Europe, the Wildcat was the only United States Navy or Marine fighter in World War II 1941–42 in the Pacific Theater besides the brief appearance of the F2A Buffalo. With a top speed of 318 mph (512 km/h), the Wildcat was outperformed by the more nimble 331 mph (533 km/h) Mitsubishi Zero, but its ruggedness and tactics such as the Thach Weave resulted in an air combat kill-to-loss ratio of 5.9:1 in 1942 and 6.9:1 for the entire war.
Lessons learned from the Wildcat were applied to the faster F6F Hellcat which could outperform the Zero on its own terms. The Wildcat continued to be built throughout the remainder of the war to serve on escort carriers, where larger and heavier fighters could not be used.