The first military aviation insignias of the United States include a star used by the US Army Signal Corps Aviation Section, seen during the Pancho Villa punitive expedition, just over a year before American involvement in World War I began. The star was painted only on the vertical tail, in either red (the most often used color) or blue (less likely, due to the strictly orthochromatic photography of that era, rendering the red star as a black one in period photos). At the same time, the US Navy was using a blue anchor on the rudders of its seaplanes.