What is the Air Force's birthday?

The Air Force's birthday is celebrated on September 18, 1947. This date marks the official establishment of the United States Air Force as a separate branch of the military when it was formed from the Army Air Forces following the National Security Act of 1947. This was a significant moment in U.S. military history as it recognized the importance of air power and the need for a distinct air force to address aerial warfare needs.

Other dates, while significant to U.S. history or other branches of the military, do not pertain to the formation of the Air Force. For example, October 13, 1775, is recognized as the birth date of the U.S. Navy, July 4, 1776, marks American Independence Day, and January 1, 1941, does not hold any particular significance in the context of the Air Force's establishment. Therefore, the choice of September 18, 1947, accurately reflects the founding of this key military branch.