TLS, one page, 7.25 x 10.5, personal letterhead, August 4, 1941. Ford writes to General H. H. “Hap” Arnold (1886–1950), who helped develop the Air Force into a unified separate service. In full: “I was happy to receive your letter of July 29 with birthday congratulations, and value your appreciative expression for the Ford Motor Company’s part in the building of planes for the Army Air Forces. Thank you for the courtesy of writing. May I extend every good wish….” Ford was evidently alluding to his gargantuan Willow Run Bomber Plant near Ypsilanti, Michigan, which began limited production a few months later. Though the plant, which boasted a mile-long assembly line and more than 2.5 million square feet of floor space, got off to an unsteady start, it was turning out a B-24 bomber every 63 seconds by the end of World War II. Small paperclip impression/stain to top edge, two small rust stains to body, and mild handling wear, otherwise fine, bright condition. Auction LOA John Reznikoff/PSA/DNA and R&R COA.