Essentially the same design, although abridged, as the air mail stamp of the
same denomination issued six months earlier, this physically smaller version
had a need.
Smaller sized stamps are more suitable for stamp rolls (known as "coils"),
stamp vending machines, and booklets.
The Douglas DC-4 Skymaster was developed during World War II and led to the DC
-6 and DC-7 series with pressurized cabins.
The rapid development of aircraft was brought about by U.S. dominance of air
transportation during and after World War II. In 1951 the United States built
more than 80 percent of the world's airliners.