The United States Army Air Service (USAAS) 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.

The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal Corps, the USAF was established as a separate branch of the United States Armed Forces in 1947 with the enactment of the National Security Act of 1947. It is the second youngest branch of the United States Armed Forces and the fourth in order of precedence. The United States Air Force articulates its core missions as air supremacy, global integrated intelligence, surveillance and reconnaissance, rapid global mobility, global strike, and command and control.