Today in World War II History—Sept. 21, 1942 POSTED: Thursday, September 21, 2017 by Sarah Sundin Boeing XB-29, 1942 (US Air Force photo) 75 Years Ago—Sept. 21, 1942: British and Indian troops launch assault into the Arakan Peninsula in Burma. First test flight of Boeing XB-29 Superfortress heavy bomber in Seattle.