Commissioned into the U.S. Navy in 1949, Carpenter became a naval aviator, flying a Lockheed P-2 Neptune with Patrol Squadron 6 (VP-6) on reconnaissance and anti-submarine warfare missions along the coasts of Soviet Union and China during the Korean War and the Cold War. In 1954, he attended the U.S. Naval Test Pilot School at NAS Patuxent River, Maryland, in 1954 and became a test pilot. In 1958 he was named Air Intelligence Officer of , which was then in dry dock at the Bremerton Navy Yard.