The Civil Air Patrol (CAP) is the official civilian auxiliary of the United States Air Force (USAF). It was created on 1 December 1941 (just days before the attack on Pearl Harbor), and is credited with sinking at least two German U-boats during World War II. Today, CAP is no longer called on to destroy submarines, but is instead a benevolent entity dedicated to education and national service. It is a volunteer organization with a strongly aviation-minded membership that includes people from all backgrounds and walks of life. It performs three key missions: emergency services (including search and rescue), aerospace education for youth and the general public, and cadet programs.

During World War II, the Civil Air Patrol was seen as a way to actively use America's civil aviation resources to aid the war effort instead of grounding them (as was the case in Great Britain.) The organization eagerly assumed many missions, including anti-submarine patrol and warfare, border patrols, and courier services. Despite being a volunteer force that was largely untrained in combat and military science, the organization's performance far exceeded expectations.

After the end of World War II, the Civil Air Patrol became a civilian auxiliary of the United States Air Force. The incorporation charter declared that CAP would never again be involved in direct combat activities, but would instead be of benevolent nature. CAP still actively performs search and rescue missions within the United States. The September 11 attacks on the World Trade Center demonstrated the importance of the Civil Air Patrol, as it was this organization's aircraft that flew blood to victims of the attack; they also provided the first aerial pictures of the World Trade Center site.