Airmail turns 100: The first U.S. mail flight occurred on May 15, 1918.
The first airmail flight took place on May 15, 1918, along a route that linked Washington, Philadelphia and New York. The distance of the route was 218 miles, and one round trip per day was made every day except Sunday. Army Air Service pilots flew the route until August 10, 1918, when the Post Office Department took over the operation with its own airplanes and pilots. Col. E.A. Deeds, head of the Aviation Section of the Signal Corps, offered to operate the postal route with military planes and pilots because of a request from Europe in World War I that pilots gain more cross-country experience before being sent overseas. Above is a modified de Havilland DH-4 that could carry 1,000 pounds of mail (twice as much as a regular de Havilland mail plane). Postal officials nicknamed it the “pregnant cow.”