Department and various theatres of operation. Meanwhile, the Navy created the Officer Messenger Service and the Army Air Corps operated an Air Courier Service to move cryptographic materials. Frequently, couriers from all three services flew together on the routes.

In November 1946, the War Department discontinued the Army Courier Service and established a "Security Courier Service," which operated until 1949. At this time, certain courier stations were transferred to the newly created U.S. Air Force Security Courier Service. Then in