The Consolidated B-24 Liberator was an American heavy bomber, designed and largely built by the Consolidated Aircraft Company of San Diego, California. The B-24 ended World War II as the most produced American aircraft of history, at over 18,000 examples, thanks in large measure to Henry Ford and the harnessing of American industry by using the assembly-line method. It still holds the record as the most-produced American military or naval aircraft. Throughout 1942 and 1943, Consolidated Aircraft tripled the size of its plant in San Diego and built a large new plant outside Fort Worth, Texas. More B-24s were built by Douglas Aircraft in Tulsa, Oklahoma. North American Aviation built a plant in Dallas, Texas, which produced B-24Gs and B-24Js. None of these were minor operations, but they were dwarfed by the vast new purpose-built factory constructed by the Ford Motor Company at Willow Run near Detroit, Michigan, which opened in August 1942 and began mass production in August 1943. This was the largest factory in the United States, and the largest anywhere outside the USSR. At its peak, the Willow Run plant produced 428 B-24s per month. Many pilots slept on cots at Willow Run while waiting for their B-24s to roll off the assembly line.