Boeing MB-3A AS.68264 "The Hawk" US Army Air ServiceThese are 1 72 scale decals for Boeing built MB 3A AS. 68264 "The Hawk", the personal aircraft of Brigadier General Billy Mitchell, United States Army Air Service. Billy Mitchell was the most outspoken and visionary advocate for air power in American military history. As Assistant Chief of the Air Service in the early 1920s, he championed the strategic potential of military aviation at a time when the Army and Navy establishment largely dismissed it.