By deliberation and a bit of happenstance, the national star insignia on American military aircraft has evolved since 1917. Mutations give warbird restorers many options, and occasional confusion results from changes that can only be understood in the context of six major iterations.

In the height of World War I, the United States adopted its first official insignia, consisting of a white star on a blue disc, with a free-floating red center (Photo 1). (Previous attempts at insignia, less than official, included the use of a red star in 1916 on some aircraft, and a roundel of red, white, and blue.) The official 1917 device handily combined red, white, and blue with a star reminiscent of the U.S. flag. This style sufficed until July 1942. By then, seven months into war with Japan, experience showed the red center to the insignia caused gunners to mistake it for the Japanese red disc. The red was taken out as an expedient (Photo 2), and some vintage photos show aircraft with obviously doctored centers.

A year later, desiring to return red to all three national colors, the military adopted an insignia that placed two white bars aside the star, and surrounded the whole device with a red border (Photo 3). It was believed the non-circular nature of this emblem would not confuse those gunners. Not so. Some warplanes in the Pacific were given white bars, but no red outline (Photo 4). Two months later, in September 1943 the red outline was ordered painted over with insignia blue. This winged blue-and-white insignia remained in use throughout the remainder of the war and into the early postwar era (Photo 5). It owes its shape to the original red outline that surrounded other elements of the insignia. It gives the appearance of floating the star and bars in a sea of blue. The rationale is only evident when one looks at the short-lived red outline variant.

When confusion with Japanese warplanes was no longer an issue, in January 1947 red bars were added to the national insignia (Photo 6).

All six examples of U.S. star insignia are present at AirVenture 2008 in the Warbirds area, making a fun scavenger hunt.