He started out with 15 employees. The company’s first production order was for $7,672 worth of parts for Stinson observation planes, and business expanded as the war began. By 1941, McDonnell had 400 employees. During World War II, the company manufactured 7 million pounds of aircraft parts and its payroll reached 5,212. It supplied tails and engine cowlings for Boeing bombers and Douglas transport and was contracted to build a few Fairchild AT-21 trainers.