During the period leading up to World War II, through the end of the Korean war, Thompson Products was a key manufacturer of component parts for aircraft engines, including cylinder valves. The TAPCO plant, owned by the U.S. government but operated by Thompson Products, extended for almost a mile along Cleveland's Euclid Avenue. It employed over 16,000 workers at the peak of WW II production. As jet aircraft replaced piston-engined aircraft, Thompson Products became a major manufacturer of turbine blades for jet engines