Airmail: Winged Airmail Letter, Symbol

 1977 United Nations Airmails

As with most airmail stamps, this set shows the link between flight and the mail.  The 25¢ shows an airmail letter with wings and the 31¢ shows a plane crossing the globe.

Airmail plays a large part in the modern postal system. Large trucks carry the mail to airports, where it is loaded onto planes. Since 1975, nearly all first class mail going more than 200 miles has traveled by plane.