The CAP insignia, a red three-bladed propeller in the Civil Defense white-triangle-in-blue-circle, began appearing on private aircraft everywhere. CAP initially planned only on liaison and reconnaissance flying, but the civilian group's mission expanded when German submarines began to prey on American ships off the coast of the United States and CAP planes began carrying bombs and depth charges."

A CAP crew first interrupted a sub attack on a flight out of Rehoboth Beach, saving a tanker off Cape May, N.J. Since radio calls for military bombers were often unproductive, unarmed CAP fliers dived in mock attacks to force subs to break and run.

The CAP coastal patrol flew 24 million miles, found 173 submarines, attacked 57, hit 10 and sank two. By Presidential Executive Order, CAP became an auxiliary of the Army Air Forces in 1943. A German commander later confirmed that coastal U-boat operations were withdrawn from the United States "because of those damned little red and yellow airplanes."

In all, CAP flew a half-million hours during the war, and 64 CAP aviators lost their lives in the line of duty.

The U.S. Air Force was created as an independent armed service in 1947, and CAP was designated as its official civilian auxiliary the following year.