AMERICAN MILITARY ROUNDELS
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 (text wikipedia).
To identify an unknown insignia for you Global Military Aviation Photography colledted the insigina’s from all over the world to make it easy to identfy for you.