Stewart returned to the United States in early fall 1945. He continued to play a role in reserve of the Army Air Forces after the war, and was also one of the 12 founders of the Air Force Association in October 1945. Stewart would eventually transfer to the reserves of the United States Air Force after the Army Air Forces split from the Army in 1947. On July 23, 1959, Stewart was promoted to brigadier general, becoming the highest-ranking actor in American military history. During the Vietnam War, he flew as a non-duty observer in a B-52 on an Arc Light bombing mission in February 1966. He served for 27 years, officially retiring from the Air Force on May 31, 1968, when he reached the mandatory retirement age of 60. Upon his retirement, he was awarded the United States Air Force Distinguished Service Medal. Stewart rarely spoke about his wartime service, but did appear in an episode of the British television documentary series "The World at War" (1974), commenting on the disastrous 1943 mission against Schweinfurt, Germany. In 1985, Stewart was promoted to rank of major general on the Air Force retired list.