In 1942, Tordoff enlisted in the U.S. Army Air Forces, and trained as a fighter pilot. He later recounted that he naively imagined flying as thrilling, and a way to avoid ground combat. His depth perception was low by Air Force standards, so he passed his vision test by watching another pilot candidate get tested, and figuring out how the settings worked on the apparatus that was used. In 1943 he earned his wings, and joined the 352nd Fighter Squadron, 353rd Fighter Group, 8th Air Force. He flew a total of 85 missions during the war, in support of the Allied bombing of Germany, and reached the rank of captain.