Photo image of <a href="https://en.wikipedia.org/wiki/Airmails_of_the_United_States" class="extiw" title="en:Airmails of the United States">U.S. Airmail stamp</a>, 6c, 1938 issue
<a href="https://en.wikipedia.org/wiki/Bureau_of_Engraving_and_Printing" class="extiw" title="wikipedia:Bureau of Engraving and Printing">Bureau of Engraving and Printing</a>; Imaging by <a href="//commons.wikimedia.org/wiki/User:Gwillhickers" title="User:Gwillhickers"><i>Gwillhickers</i></a>
1938
U.S. Post Office; Smithsonian National Postal Museum