The U.S military operations in the air started off with the use of balloons for investigations during the Spanish-American War and the American Civil War. After the WWI, the Air Force Service was rapidly reduced to a small fraction of its earlier power. Mitchell became a strong exponent of the movement to initiate a split air force on parity with the navy and the army. Regardless of his efforts, the Army Reorganization Act implemented in 1920 made it a combatant unit in the army. At this time, the Air Corps Act of 1926 made the Armed Air Corps to substitute the Air Service, which was responsible for the logistical support and training of its units, whereas the tactical units were controlled by the Army orders (Stiehm, 2000)
On the eve of the Second World War, dated September 1939, the air arm of the army had a total of 25,000 men and officers and close to 1,500 tactical planes. However, in 1940, the Air Corps were given a role to expand their operations in response to the European events of the time. In March 1942, following American involvement into the war, the entire service unit was merged with the Army Air Forces, which was directed with the extension of the air arm.
During the WWII, the 8th and 15th Air Forces took part in the tactical bombing of Germany, along with the Royal Air Force Bomber Command.