Curtiss PW-8s (later P-1 Hawk) of the 1st Pursuit Group warm up prior to attempting 1-day flight from Selfridge Field, Michigan to Miami, Florida
United States Air Force
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.