The 111th Fighter Squadron began as the 111th Aero Squadron on 14 August 1917 at Kelly Field, TX. The unit, composed of teamsters and laborers, was on special duty at Kelly and was known as the "Post Headquarters Squadron." The squadron deactivated 19 August 1919 but was called to service again on 29 June 1923 in the old Houston Light Guard Armory, as the 111th Observation Squadron, 36th Division, Texas Air National Guard.