Air Mail Biplane Jigsaw Puzzle

Regular airmail or air mail service was inaugurated in the United States on May 15, 1918 with the first service route between Washington, D.C., Philadelphia, and New York City. International airmail began a year later and designed Par avion, which means by airplane. Balloons, dirigibles and biplanes were first to carry the letters and packages. More reliable service came with metal multiengine planes and eventually jet aircraft.