The FM Wildcat, an improved version built by General Motors, remained in service throughout the remainder of the war on escort carriers, where larger and heavier fighters could not be used.
Grumman's Wildcat production ceased in early 1943 to make way for the newer F6F Hellcat, but General Motors continued producing Wildcats for both US Navy and Fleet Air Arm use. From 1943 onward, Wildcats were primarily assigned to escort carriers ("jeep carriers") as larger fighters such as the Hellcat and the Vought F4U Corsair were needed aboard fleet carriers, and the Wildcat's slower landing speed made it more suitable for shorter flight decks. At first, GM produced the FM-1 (identical to the F4F-4, but with four guns). Production later switched to the improved FM-2 (based on Grumman's XF4F-8 prototype) optimized for small-carrier operations, with a more powerful engine, and a taller tail to cope with the torque. In all, 7,860 Wildcats were built.