The 55-cent Billy Mitchell definitive stamp was issued in Milwaukee, Wisconsin, on July 30, 1999. The stamp was designed by Phil Jordan of Falls Church, Virginia, and illustrated by Paul Salmon of Burke, Virginia.
General William "Billy" Mitchell was a professional soldier who served as an infantryman in the Spanish-American War and went on to achieve greater fame as an outstanding US combat air commander during World War I. The stamp art is based on an early photograph of Mitchell, and the foreground shows the SPAD XVI, which he used in observation and command roles during World War I.
100.75 million gravure stamps were manufactured by Guilford Gravure.
Postal Bulletin (July 1, 1999).