1957 United Nations Airmail
All U.N. airmail stamps are illustrated with the symbols of flight. They show stylized planes or birds along with the U.N. emblem. This 5¢ stamp features an airplane wing and the globe.
The United States Post Office began airmail service in 1918, using modified military planes to fly mail between a few large cities. The first airmail stamps of the U.N. were issued in 1951.