This kepi is an example of the type worn by Foreign Legion in the French Army during the First World War. This kepi was worn by Kiffin Rockwell in the French Air Service. It was not unusual for individuals that transferred to the air service to continue to use the uniform of their original service branch.

Kiffin Rockwell flew with the Lafayette Escadrille during World War I. Kiffin and his brother Paul went to France in August 1914 and joined the French Foreign Legion. Kiffin entered combat in the winter of 1915 and was severely wounded at Neuville-Saint-Vaast later that May. Following a lengthy convalescence, Kiffin obtained a transfer to the French Air Service and was one of the original members of the Escadrille Lafayette, a squadron of American pilots flying for France. Rockwell shot down his first of four German aircraft on May 18, 1916, in Alsace. On September 23, 1916, he was shot down over Verdun and buried at Luxiul. For his services to France, Rockwell was awarded the Medaille Miliataire and the Croix de Guerre with two palms.