According to the Willow Run Reference Book published 1 February 1945, Ford broke ground on Willow Run on 18 April 1941, with the first plane coming off the line on 10 September 1942. Willow Run had the largest assembly line in the world (). At its peak in 1944, the Willow Run plant produced one B-24 per hour and 650 B-24s per month. In mid-1944, the production of the B-24 was consolidated from several different companies (including some in Texas) to two large factories: the Consolidated Aircraft Company in San Diego and the Ford Motor Company's factory in Willow Run, near Detroit, Michigan, which had been specially designed to produce B-24s. By 1945, Ford made 70% of all B-24s in two nine-hour shifts. Pilots and crews slept on 1,300 cots at Willow Run waiting for their B-24s to roll off the assembly line. At Willow Run, Ford produced half of 18,000 total B-24s alone. Up into December 1944, Ford had also produced an additional 7242 KD or 'Knock Down' Kits that would be trucked to and assembled by Consolidated in Ft. Worth and Douglas Aircraft in Tulsa. Each of the B-24 factories was identified with a production code suffix: Consolidated/San Diego, CO; Consolidated/Fort Worth, CF; Ford/Willow Run, FO; North American, NT; and Douglas/Tulsa, DT.