The 15-cent Gaillard Cut airmail stamp (Scott C10) of this series is one of the originals issued on November 18, 1931. It was first intended for airmail letters to nearby Latin American and Caribbean countries, but its greatest use occurred between December 10, 1937, and March 31, 1945, when the airmail rate to the United States was fifteen cents. In addition, it was commonly used in combination with other stamps such as on overweight, foreign, registered, and special delivery letters and packages.
Some 62,500 (the most of any of the airmails) of these stamps were overprinted between 1941 and 1952 for official use by Canal Zone-based federal offices. This stamp is known as one of the 'The Official Airmails'. (Scott CO3)
First day covers from 1931 are scarce, but they are often found with the 5-cent Gaillard Cut airmail stamp to make-up the twenty-cent rate on the November 25, 1931, Lindbergh flight.
The airmail cover depicted is a typical use of the 15-cent Gaillard Cut airmail stamp on a one ounce letter to the United States. However, a canceling machine malfunction makes the exact date illegible, though it appears that the year is 1942. Note that this letter's contents were examined (censored) in the United States upon arrival from the Canal Zone. The "Via Air Mail" handstamp was privately applied, but it adds interest to this otherwise common cover.