Aircraft roundel
Military aircraft insignia are insignia applied to military aircraft to identify the nation or branch of military service to which the aircraft belongs. Many insignia are in the form of a circular roundel or modified roundel; other shapes such as stars, crosses, squares or triangles are also used.
Insignia are often displayed on the sides of the fuselage, the upper and lower surfaces of the wings, as well as on the fin or rudder of an aircraft, although considerable variation can be found amongst different air arms, and within specific air arms over time.
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The first use of national insignia on military aircraft was before the First World War by the French Aéronautique Militaire which mandated the application of roundels in 1912. The chosen design was the French national cockade, which consisted of a blue-white-red emblem, going outwards from center to rim, mirroring the colours of the flag of France. In addition, the rudders of the aircraft were painted the same colours in vertical stripes, with the blue vertical stripe of the tricolors forwardmost. Similar national cockades were designed and adopted for use as aircraft roundels by the air forces of other countries, including the U.S. Army Air Service.
Of all the early operators of military aircraft, Germany was unusual in not using "round" roundels, but after evaluating several possible markings, including a black, red and white checkerboard, and a similarly coloured roundel, and black stripes, a black "iron" cross on a square white field was chosen as it was already in use on various flags, and to reflect Germany's heritage as the Holy Roman Empire. The German army's mobilization led to orders in September 1914 to paint all-black Eisernes Kreuz (iron cross) insignia with wide-flared arms over a white field — usually square in shape — on the wings and tails of all aircraft flown by its air arm, then known as the Fliegertruppe des Deutschen Kaiserreiches. The fuselage was also usually marked with a cross on each side but this was optional. The form and location of the initial cross was largely up to the painter, which led to considerable variation, and even the white being omitted. An iron cross with explicit proportions superseded it in July 1916, whose initial form was also painted on a white field, although this would be reduced to a 5 cm border completely around the cross in October of the same year — the month of the formation of the Army's Deutsche Luftstreitkräfte in name — even bordering the ends of the flared arms' ends. In March 1918, a straight black cross with narrow white borders on all sides of the cross was ordered, but proportions were not set until April, resulting in many of those repainted in the field having non-standard proportions. This was then replaced by a narrower, straight-armed cross in May that extended the full chord of wings, with the white border restricted to the sides of the cross's bars. In June, it ceased to be used full chord, with the bars all being the same length. The white on any of these could be omitted when used on a white background, such as was used sometimes for the rudder, and was sometimes omitted on night bombers.
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