Historical research has indicated that from 1942 to 1949 the following method of Aircraft marking ensued within CAP. Based originally upon Army Air Corps (AAC) and later US Army Air Force (USAAF) Directives that describes placement of identifying markings on all military aircraft.

The design by it circular nature readily addressed itself to be used as a rondelle. CAP Regulations, Memorandums and Directives all called for the proper placement, and size relationship to the aircraft to which it was applied. Aircraft Civil Aeronautics Administration (CAA) numbers placement should comply with a practical sense for CAP is the Mission

Operational Directive No. 2 February 12, 1942, (OD No. 2) – National Headquarters, Civil Air Patrol Office of Civilian Defense (Washington)

The Civil Air Patrol insignia (blue disk with superimposed white triangle and with red three-bladed propeller superimposed on white triangle) shall be placed on the wings and fuselage of all aircraft engaged in official Civil Air Patrol Missions. Any aircraft while displaying such insignia shall be flown exclusively by members of the Civil Air patrol.

Insignia disks placed on wings shall be centered on the topside of the left wing and the bottom side of the right wing at a point one-third of the distance from wing tip to the fuselage. The diameter of said disks shall not exceed two-thirds of the wing cord at point of application

Insignia disks placed on the fuselage shall be centered on both sides of the fuselage at a point one-third of the distance from the leading edge of the horizontal stabilizer to the trailing edge of the wing. The diameter of said disks shall not exceed two [thirds of the depth of the fuselage at the point of application.

General Memorandum-29, May 25 1942, (GM-29) with special classified addendum only for Coastal Patrol personnel and operations section. Now required the removal of the red three bladed propeller from the CAP aircraft emblem on all aircraft assigned. The official CP insignia now consisted of a blue circle with white isosceles triangle was the only authorized insignia for CAP-CP aircraft This was in keeping with the current practice of the AAF to avoid confusion with Japanese emblem. This directive and practice remained in effect till the Coastal Patrol units were disbanded in 1945.

But throughout CAP’s war time efforts duties and reassignments as its transfer from the Office of Civilian Defense, to the War Department on 23 April 1943, to the Commanding General Army Air Forces on 4 May 1943, it was always directed that all other CAP aircraft assigned and/or used for, Border, Forest, Tow Target, Search-Light Spotting, Liaison, Courier and Missing Aircraft Search service were directed to use the standard Civil Air Patrol insignia which included the red 3 bladed propeller.