Description
Kelly Field is in San Antonio, Texas. Kelly Field was one of thirty-two Air Service training camps established after the United States entry into World War I, being established on 27 March 1917.[2] It was used as a flying field; primary flying school; school for adjutants, supply officers, engineers; mechanics school, and as an aviation general supply depot.[
Hi was stationed there early in his military life and received training as an airplane mechanic.
https://en.wikipedia.org/wiki/Kelly_Field#cite_note-3
Back marked with number "0838" and stamped by "Fox Tone San Antonio, Texas"