The United States Air Force (USAF) is the aerial and space warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the U.S. Armed Forces on 18 September 1947 under the National Security Act of 1947.It is the most recent branch of the U.S. Armed Forces to be formed. Show your Air Force pride by wearing this patch on your flight suit or bomber jacket. This patch is sold individually and comes with hook-and-loop fasteners.