The United States Air Force is the aerial and space warfare service branch of the United States Armed Forces. Initially established as a part of the United States Army on August 1, 1907, the USAF was formed as a separate branch of the U.S. Armed Forces on September 18, 1947 with the passing of the National Security Act of 1947. It is the youngest branch of the U.S. Armed Forces, and the fourth in order of precedence.
The USAF is the largest and most technologically advanced air force in the world. The Air Force articulates its core missions as air and space superiority, global integrated ISR, rapid global mobility, global strike, and command and control. Along with conducting independent air and space operations, the U.S. Air Force provides air support for land and naval forces and aids in the recovery of troops in the field with with 318,415 active duty personnel, 140,169 civilian personnel, 69,200 Air Force Reserve personnel, and 105,700 Air National Guard personnel.