In 1939 Vandenberg joined the Plans Division under Lieutenant General Henry H. "Hap" Arnold, chief of the U.S. Air Corps. Vandenberg's excellent staff work directing the rapid air force expansion consequent to the start of World War II won him promotion to colonel in 1942. In the summer of 1942 he moved to Britain to work on air support for the forthcoming North African invasion. Promoted to brigadier general that December, he accompanied Major General James Harold Doolittle to Northwest Africa as his chief of staff, flying twenty-six combat missions and attending the 1943 Quebec, Tehran, and Cairo Conferences. In August 1944 Vandenberg took command of the Ninth Air Force of more than 4,000 aircraft that provided tactical support to Allied ground forces throughout the West European theater. He was promoted to major general in March 1945.
Following staff appointments in Washington, in 1946 Vandenberg became director of the Central Intelligence Group, forerunner of the Central Intelligence Agency (CIA), substantially expanding and centralizing its activities. Promoted to full general in October 1947 and appointed the newly independent U.S. Air Force's vice chief of staff under General Carl "Tooey" Spaatz, six months later Vandenberg succeeded him. Almost immediately, the air force was confronted by the Berlin Blockade and for fifteen months sustained a massive airlift to keep West Berlin supplied. Vandenberg advocated a seventy-group air force, but President Harry S. Truman's stringent budgetary policies initially restricted him to fifty-five or fewer. Vandenberg concentrated resources on developing strategic air offensive capabilities, ably presenting air force views in the heated 1949 controversy over the U.S. Navy's strategic deterrent role, and strongly supported development of the hydrogen bomb.
When the Korean War began in June 1950, the air force quickly established air superiority in Korea and provided vital support to United Nations (UN) ground forces. The war also brought the expansion that Vandenberg had long advocated, doubling the air force to 106 wings, although he furiously protested the decision to defer for several years after his June 1953 retirement a promised further increase to his ideal 143 wings. Vandenberg died in Washington, D.C., on 2 April 1954. His indefatigable efforts to build up the air force effectively ensured the United States a Cold War strategic striking strength far surpassing that of any other nation.
Parrish, Noel F. "Hoyt S. Vandenberg: Building the New Air Force." Pp. 205–228 in Makers of the United States Air Force. Edited by John L. Frisbee. Washington, DC: U.S. Government Printing Office, 1987.; Reynolds, John. "Education and Training for High Command: General Hoyt S. Vandenberg's Early Career." Unpublished PhD diss., Duke University, 1980.; Smith, Robert. "The Influence of USAF Chief of Staff Hoyt S. Vandenberg on United States National Security Policy." Unpublished PhD diss., American University, 1965.