Image of three airmail stamps, Curtis Jenny, 6c, 16c, 24c
Bureau of Engraving and Printing; Imaging and composite photo by <a href="//commons.wikimedia.org/wiki/User:Gwillhickers" title="User:Gwillhickers"><i>Gwillhickers</i></a>
1913, 1918
U.S. Post Office; Smithsonian National Postal Museum