D-57 Airship Pony Blimp Used for training at the Baloon and Airship School.  D-57 was a K-Class blimp built by the Goodyear Aircraft company of Akron Ohio, primarily for the United States Navy
United States Air Force
1920
Maurer Maurer, 1987, Aviation in the US. Army, 1919-1938, United States Air Force Historical Research Center, Office of Air Force History,  United States Air Force, Washington, D.C.