I assume that you are writing of the insignia found on some of the Escadrille aircraft, such as that of Lufbury, which depicts the head of a Seminole Indian Chieftain, and which has a small swastika located over the ear on his headband. (This is the same as the insignia on the Escadrille banner which you linked to your question.) This insignia for the Escadrille (French Squadron number SPA-124) was designed by Harold Willis, presumably to illustrate the American origin of the pilots, and the legendary martial skills of the American Indians, though I have not found a contemporary reference to the actual rationale for this insignia. (Reference: Editions Atlas, Paris, 1992, "L'Armée De l'Air (1)). It must be noted that the Swastika is an ancient good luck symbol, and was used in that context by many cultures before it was defamed by the Nazis-- In fact, the United States had an Infantry Division, the 45th, which wore a Swastika as its shoulder patch from 1924 until shortly before WW2. This was in honor of the SW United States region, which had a large population of Native Americans. Other countries, Finland for example, used the Swastika on aircraft during both WWI and WW2. (ref Aircraft Markings of the world 1912-1967, Bruce Robertson, Harleyford Pubs UK, 1967).