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 by two executive orders of President Woodrow Wilson: on May 24, 1918, replacing the Aviation Section, Signal Corps as the nation's air force; and March 19, 1919, establishing a military Director of Air Service to control all aviation activities. Its life was extended for another year in July 1919, during which time Congress passed the legislation necessary to make it a permanent establishment. The National Defense Act of 1920 assigned the Air Service the status of "combatant arm of the line" of the United States Army with a major general in command.