This 15-cent airmail (Scott C17) was issued on July 15, 1939, as part of the six-stamp series marking the tenth anniversary of airmail service in the Canal Zone as well as the 25th anniversary of the opening of the Panama Canal. It was intended to be used on single-weight airmail letters to the United States as well as a number of Central American and Caribbean addresses. The design contains an side view of a typical Pan American clipper ship of the time against an allegorical view of the Pacific Entrance of the Panama Canal from a vantage point in the vicinity of the US Army post at Fort Amador. In reality, however, collectors usually just refer to it as 'The 15-cent Anniversary Airmail'.
Some 885,000 were shipped to the Canal Zone, and after sale of stamps from this series was halted on February 28, 1941, only 1,258 had to be burned with the other unsold remainders on April 12, 1941.
First day covers of this stamps are common, both as singles and in combination with other stamps from this series. It was widely used and examples of it from all Canal Zone post offices may be acquired. It was also utilized in large numbers in a 'make-up' rate capacity, and these examples are very popular among collectors.