The U.S. Air Force was officially established as a separate branch of the military on September 18, 1947. This formal creation came about through the National Security Act of 1947, which reorganized the military structure after World War II and separated the Air Force from the U.S. Army. As of August 22, 2025, the U.S. Air Force is 77 years old, having celebrated its 77th birthday on September 18, 2024. Its origins, however, trace back much earlier, starting with the U.S. Army Signal Corps' Aeronautical Division established in 1907, evolving through various forms such as the Army Air Forces during World War II before becoming its own independent service branch in 1947.
