The United States Army Air Service (USAAS) (also known as the “Air Service”, “U.S. Air Service” and before its legislative establishment in 1920, the “Air Service, United States Army”) was the aerial warfare service component of the United States Army between 1918 and 1926 and a forerunner of the United States Air Force. It was established as an independent but temporary branch of the U.S. War Department during World War I.