The USAF formally began operations on September 18th, 1947 following the conclusion of World War 2 (September 2nd, 1945) but maintained a history as far back as 1907. Before 1947, the USAF operated as the "United States Army Air Force" (USAAF) when American airmen contributed to both World War 1 (1914-1918) and World War 2 (1939-1945). The modern United States Air Force has seen major combat actions since the Korean War (1950-1953) and fields a variety of attack, bomber, helicopter, reconnaissance, training and transport aircraft to cover all manner of mission types.
NOTES: The Five Star rank is generally reserved for wartime only and may also be used as an honorary rank. Formally, United States Air Force rank abbreviations are not displayed with an ending period. Additionally, the United States Air Force does not maintain a First Sergeant rank common to other branches of service. Instead, Sergeant ranks are denoted by special additions within the insignia, such as the diamond differentiating the Master Sergeant and Senior Master Sergeant ranks. Similarly, the diamond is replaced by a star to differentiate between the Chief Master Sergeant and Command Chief Master Sergeant ranks.