The United States Army Air Service (officially the Air Service, United States Army) was a forerunner of the United States Air Force during and after World War I. It was established as an independent but temporary wartime branch of the War Department by two executive orders of President Woodrow Wilson. On May 24, 1918, replacing the Aviation Section, U.S. 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.