Question: During World War II, Ford’s enormous Willow Run plant near Ypsilanti mass-produced what heavy bomber, turning out roughly one an hour at its 1944 peak?

Answer: The B-24 Liberator. Ford applied its auto assembly-line know-how to aircraft at Willow Run, and by 1944 the plant was finishing a Liberator about every hour, a feat that helped make it a symbol of America’s “Arsenal of Democracy.”