As aircraft began to be a practical mode of transportation, the military role in their development actually increased. After World War I, cheap surplus military airplanes and aircraft engines gave civilian aviation a push start. The airplanes used for barnstorming and the earliest regular airmail service were military surplus planes.
Air Mail Plane on Display in Times Square in New York City, 1934.
Photo: Post Office Department. Bureau of the Second Assistant Postmaster General.
National Archives and Records Administration.
Still Picture Branch; College Park, Maryland.