United States. Army. Division, 91st

During World War I, the 91st Observation Squadron of the American Expeditionary Force operated reconnaissance missions 15 to 25 miles beyond enemy lines. They informed A.E.F. Headquarters of movements on roads and airdromes and in railroad yards, which they observed from above 15,000 feet; they also reported on supply and ammunition dumps.

The 91st Squadron arrived in Liverpool, England with the 90th and 88th Squadrons in November 1917 and traveled to Hill 402 to construct an airfield next to the American Expeditionary Force Headquarters in Chaumont, France. The squadron then traveled to Amanty, France where a school for pilots was operated. However, flight training was delayed by the lack of adequate airplanes; well into 1918, only worn-out Dorand, Sopwith and SPAD aircraft were available for use. Sixteen Salmson airplanes arrived by May of 1918, enabling the Squadron, with mediocre gunnery training, to begin operations.

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