When was the United States Air Force founded?
United States Air Force
USAF rank is divided between enlisted airmen, non-commissioned officers, and commissioned officers, and ranges from the enlisted Airman Basic (E-1) to the commissioned officer rank of General (O-10), however in times of war officers may be appointed to the higher grade of General of the Air Force. Enlisted promotions are granted based on a combination of test scores, years of experience, and selection board approval while officer promotions are based on time-in-grade and a promotion selection board. Promotions among enlisted personnel and non-commissioned officers are generally designated by increasing numbers of insignia chevrons.[55] Commissioned officer rank is designated by bars, oak leaves, a silver eagle, and anywhere from one to five stars.[56] General of the Air Force Henry "Hap" Arnold is the only individual in the history of the US Air Force to attain the rank of five-star general.[57]