September 18 in American History

September 18, 1947 — the U.S. Air Force is established

The National Security Act split the Army Air Forces off into its own independent branch, recognizing that air power had become its own kind of warfare rather than an extension of ground combat. The newest of the older branches — and, until the Space Force in 2019, the last one created.

★ Founding DaySeptember 18 marks U.S. Air Force — since 1947

Common Questions About September 18

What happened on September 18 in American history?

In 1947: the U.S. Air Force is established. The National Security Act split the Army Air Forces off into its own independent branch, recognizing that air power had become its own kind of warfare rather than an extension of ground combat.

Why is September 18 significant?

The National Security Act split the Army Air Forces off into its own independent branch, recognizing that air power had become its own kind of warfare rather than an extension of ground combat. The newest of the older branches — and, until the Space Force in 2019, the last one created.

Is September 18 an American holiday or anniversary?

Yes — September 18 marks the anniversary of U.S. Air Force, dating to 1947. Established as an independent branch under the National Security Act.

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