In the late 1920s, the Ford Aircraft Division was reputedly the "largest manufacturer of commercial airplanes in the world." Alongside the Ford Trimotor, a new single-seat commuter aircraft, the Ford Flivver or "Sky Flivver" had been designed and flown in prototype form, but never entered series production. The Trimotor was not to be Ford's last venture in aircraft production. During World War II, the largest aircraft manufacturing plant in the world was built at the Willow Run, Michigan plant, where Ford produced thousands of B-24 Liberator bombers under license from Consolidated Aircraft.