1938 6c Airmail Eagle, Imperf. Between Error

Own This Scarce Imperforate Airmail Stamp with Large Margin

This scarce error stamp will make the perfect addition to your collection.  The pair of C23 was supposed to be perforated horizontally, as well as vertically. Because of an error during production, the horizontal perforations weren’t applied.  The pair then slipped by the eye of postal inspectors and was discovered by a keen-eyed collector, who saw its value as an error stamp with a large margin.  Now you can make it part of your collection.

History behind the stamp: The bi-colored 6¢ airmail stamp was issued in celebration of National Airmail Week, which commemorated the 20th anniversary of the first government airmail flight.  President Franklin Roosevelt, a stamp enthusiast, was presented with some possible designs for the new stamp but sketched his own idea instead. His flying eagle became the picture on the new airmail stamp. 
The 6¢ Eagle first went on sale in Dayton, OH, the home of the Wright brothers, and St. Petersburg, FL, where the first passenger flight was made. A temporary post office was established, because the American Air Mail Society was holding its annual convention in St. Petersburg.
To celebrate the anniversary, towns all over the U.S. prepared individual First Day Covers. Most covers were mailed on Thursday, May 19 to take part in special one-day-only flights. Towns with no airport cleared fields and closed roads so the planes could land and take-off with the special envelopes. 
President Roosevelt received hundreds of covers from all over America, each bearing the stamp that he had designed.