Fisher Body Co. was a Detroit based manufacturer of automobile bodies for Chandler Motor Car Co. and Cleveland Automobile Co. It became a division of General Motors in 1926; building bodies only for General Motors. During World War II, the Fisher Body plants in Cleveland and Grand Rapids expanded production to B-29 airplanes, guns and tank parts.

The Grand Rapids Stamping Division began production of the B-29 Bomber Flap Track and Flap Track Carriage in 1942.This aircraft had a superior flying range and a bomber with increased load capacity. The B-17 bomber, predecessor to the B-29, was known as the “Flying Fortress." However, there was a need for a bomber with a higher load capacity and flying range to traverse the Pacific Ocean as a consequence of the attack on Pear Harbor in 1942. Additionally, this plant also manufactured the 120 mm AA gun mount and parts which extended over a duration of 39 months beginning in December 1941 and continuing till February 1945.