The United States Air Force was established on September 18, 1947, when the National Security Act, which made the Air Force an independent branch of the military, went into effect. Fittingly, President Harry Truman signed the law aboard The Sacred Cow, the C-54 transport plane used for presidential flights in those days.

The beginnings of an American air-going force stretch back to 1907, less than four years after the Wright Brothers’ first powered flight, when the U.S. Army Signal Corps formed an Aeronautical Division. In 1909 the Army bought its first plane, the Wright Military Flyer.

When World War I started in Europe, the Army owned only five planes. By the end of the war, military strategists realized that to win battles, they must control the skies. During World War II, the U.S. Army Air Forces reached a peak strength of 80,000 planes. The critical role of air power led Truman to make the Air Force a full partner with the Army and Navy. Today the Air Force maintains about 5,600 active aircraft.

The U.S. Air Force flag is blue and bears the Air Force coat of arms. The shield carries an image of a pair of wings, a vertical thunderbolt, and lightning flashes – all symbolizing the power to strike from the air. Above the shield, a bald eagle perches in front of a cloud. Thirteen stars surround the coat of arms, representing the thirteen original states. The top three stars also symbolize the Departments of the Army, Navy, and Air Force.