Officially known as Allied Expeditionary Air Forces Special Markings (or Invasion Stripes), these alternating series of black and white stripes were by Supreme Headquarters Allied Expeditionary Forces (SHAEF) in early 1944 by means of a top secret Operation Memorandum Number 23, entitled “DISTINCTIVE MARKING – AIRCRAFT” (the complete text of this document can be found below).

This order was issue to all USAAF and RAF aircraft units in anticipation that the German Luftwaffe would respond in great strength during Operation Overlord (D-Day landings). There was a profound fear that allied aircraft would be mistaken for the enemy by the Allied ground troups, Navy and Air Force. Experience during the landings in Sicily learned that this kind of distinctive markings greatly reduced the number of so-called “friendly-fire accidents”.

The order was effective 11am. Sunday, June 4th , 1944, and stated that no aircraft were to fly without the new markings.

The markings consisted of five alternating 18-inch wide stripes (white/black/white/black/white) around the rear fuselage and around each wing. The stripes on the wings were to be 15 inches wide.

On the wing, the outer white stripe was to be 6 inches from the national insignia. On the fuselage, the edge of the rearmost stripe was to be 18 inches from the leading edge of the tailplane, but the stripes should in no case obscure the national marking.
The outer white stripes obliterated most of the individual aircraft letter and the second letter of the squadron code. In some cases they were painted around and in others reinstated.

After invasion, the stripes were found to compromise camouflage .On July 6th, 1944 The U.S. 8th Air Force started removing upper stripes followed by many other units though no order from SHAEF has been found.
On August 1st, 1944 amendment 3 (to operational memorandum 23) ordered all wing stripes removed from August 25th onwards. Fuselage stripes were to remain intact. Many units removed the upper fuselage stripes at this time in a "liberal" interpretation of the order (the text of this amendment can be found here). This meant that the stripes now disappeared from the top half of the wings and fuselage).

In December, the remaining portion of the markings on the underside was to be deleted by the last day of the year.

On April 13th, 1944, the newly formed Supreme Headquarters Allied Expeditionary Force issued a draft of a major Operation Memorandum, Number 23, entitled "DISTINCTIVE MARKING - AIRCRAFT". This was approved very quickly and issued on April 18th, 1944.

Only 100 copies of the Top Secret document were made; 55 were issued to the necessary commands, each bearing its own number. The other 45 copies were held as spares. The following information comes from copy number 36, issued to the Chief Administrative Officer.

TOP SECRET
SUPREME HEADQUARTERS
ALLIED EXPIDITIONARY FORCE
OPERATION MEMORANDUM
NUMBER 23

TOP SECRET
Copy No. 38

18 April, 1944

DISTINCTIVE MARKING – AIRCRAFT

1. OBJECT

The object of this memorandum is to prescribe the distinctive markings which will be applied to US and BRITISH aircraft in order to make them more easily identified as friendly by ground and naval forces and by other friendly aircraft.

2. SCOPE

a. The instructions contained herein will apply to the following types of US and BRITISH aircraft: (I) Fighters and fighter bombers. (2) Tactical and photographic reconnaissance aircraft. (3) Aircraft employed in spotting for naval gunfire and field artillery. (4) Light bombers. (5) Medium bombers. (6) Troop carrier aircraft, including four engine types. (7) Glider tugs, including four engine types. (8) Liaison aircraft and Air OP's employed in forward areas for fire spotting and adjustment or for advanced aircraft control. (9) Coastal Command, Air Sea Rescue and disembarked Fleet Air Arm aircraft except seaplanes and four engine aircraft which need not be marked.
b. These instructions will not apply to the following classes of aircraft:(l) Four engine bombers. (2) Air transports. (3) Gliders. (4) Night fighters. (5) Seaplanes.

3. GENERAL

a. The instructions contained herein will be effective on the day of the assault and thereafter until it is deemed advisable to change. Aircraft will be given distinctive markings as shortly before the day of the assault as it is possible in order to protect the effectiveness of their use.
b. These instructions are in no way intended to change the present US and BRITISH national markings now in use, namely: the USAAF white star on a white horizontal bar; and the RAF red, white and blue roundel.

4. DISTINCTIVE MARKINGS

a Single engine aircraft. (I) Upper and lower wing surfaces of aircraft listed in paragraph 2 g above, will be painted with five white and black stripes, each eighteen inches wide, parallel to the longitudinal axis of the airplane, arranged in order from center outward; white, black, white, black, white. Stripes will end six inches inboard of the national markings. (2) Fuselages will be painted with five parallel white and black stripes, each eighteen inches wide, completely around the fuselage, with the outside edge of the rearmost band eighteen inches from the leading edge of the tailplane.
b. Twin engine aircraft. (I) Upper and lower wing surfaces of aircraft listed in paragraph 2 g above, will be painted from the engine nacelles outward with five white and black stripes, each twenty-four inches wide, arranged in order from center outward: white, black, white, black, white. (2) Fuselages will be painted with five parallel white and black stripes, each twenty-four inches wide, completely around the fuselage, with the outside edge of the rearmost band eighteen inches from the leading edge of the tailplane.
c. Four engine troop carrier aircraft and g lider tugs. (I) Same as for twin-engine aircraft, wing stripes to be outboard of the outer engine nacelles.
d. Stripes will in no case be painted over the national markings, which take precedence. Wing stripes will extend from leading edge to trailing edge of wings. Special equipment, such as deicer boots, will not be painted over.
e. Types of paint to be employed: (1) USAAF Units - as directed by the Commanding General of the Air Force concerned. (2) RAF Units - as directed by the appropriate BRITISH agency.
f. At Appendix' A: are sample sketches of aircraft painted according to these instructions.

5. BRIEFING

Army, Navy and Air Commanders will disseminate complete information concerning these distinctive markings to all troops under their commands no earlier before the day of the assault than will insure the complete distribution of the information.

By command of General Eisenhower:
W. B. Smith
Lieutenant General, U.S. Army,
OFFICIAL: Chief of Staff.
H. R. BULL,
Major General, G.S.C.,
Assistant Chief of Staff, G-3.

Yours 302025. Proposal to retain fuselage markings only concurred in but consider this should continue to apply to all classes of aircraft as in your memorandum number 23. Markings have proved valuable to Naval Forces where operations are not confined to Assault Area and to remove them from some classes of aircraft will cause doubt.

If it is decided to remove wing markings concede that this should be done in as short a time as possible and all concerned then informed.

Somewhat later, on August 7th, 1944, HQ Twelfth Army Group (signed Bradley), sent SHAEF Forward the following signal:

Reference SHGCT dated 30 July 1944. This Headquarters concurs in the proposed change of distinctive aircraft markings as contained therein.

Change No.4 to the Op. Memo No. 13, dated October 13,1944 ordered the removal of all stripes on Allied aircraft, but on October 25, 1944, a TWX from USSTAF to the various fighter commands stated that:

The present method of applying distinctive markings on your fighters authorized by SHAEF. By this authority you are authorized to disregard instructions contained in change no. 4 to Operations Memorandum No. 13 (29 April 1944) of HQ ETOUSA dated 13 October 1944.

Distinctive Markings on single and twin engined aircraft will be as follows:

(A) The under, repeat, under surface of fuselages of single engined aircraft will be painted with five (5) parallel white and black stripes, each eighteen (18) inches wide, with the outside edge of the rearmost band eighteen (18) inches from the leading edge of the tailplane.

(B) The under, repeat, under surface of twin engined aircraft will be painted with five (5) parallel white and black stripes, each twenty-four (24) inches wide, with the outside edge of the rearmost band eighteen (18) inches from the leading edge of the tailplane.

This meant that the stripes now disappeared from the top of the wings and fuselages of all fighter type aircraft.

This is the First Suspension/Cancellation of a SHAEF OPERATION MEMORANDUM.

SUSPENSION OF OPERATION MEMORANDUM NUMBER 23, 6th December, 1944
DISTINCTIVE MARKINGS - AIRCRAFT

1. The provisions of Supreme Headquarters, AEF, Operation Memorandum No.23, Distinctive Markings - Aircraft, are suspended effective December 31st, 1944.

2. Except as noted in sub-paragraph 44. below, distinctive markings will be removed where this can be done without damage to the aircraft and with due regard to the materials and time available for this work.

3. Addressees will ensure complete dissemination of the pertinent provisions of this suspension by the quickest possible means consistent with security.

4. All Commanders will particularly ensure that personnel under their command are instructed that:
a. The fact that an aircraft of allied manufacture is seen without distinctive markings does NOT necessarily indicate that the aircraft is hostile. b. For some time Allied aircraft may still be seen carrying distinctive markings, which, with the exception of those in sub-paragraph 4 below, should now be disregarded.
c. Faded striping under certain conditions of light closely resembles the German cross.
d. For the purposes of facilitating identification by other friendly aircraft all of the photo reconnaissance aircraft of Number 34 Wing, Second Tactical Air Force will be painted with standard invasion markings until such time as all recipients of this instruction are notified by Air Officer Commanding-in-Chief, Second Tactical Air Force.

5. The removal of these distinctive markings in no way affects the presently prescribed national markings, which will continue to be carried on aircraft.

6.In future, should there be a requirement for distinctive markings, application will be made to this Headquarters.

By Command of General EISENHOWER.