The Canal Zone Seal and Jet airmails (Scott C42-53) were issued at intervals between 1965 and 1976. The first group (6-, 8-, 15-, 20-, 30-, and 80-cent) replaced the earlier airmails on July 15, 1965. The 10-, 11-, and 13-cent stamps reflected rate changes to the United States, while the 22-, 25-, and 35-cent stamps covered new rates to the rest of the world.
The design incorporates a vignette of the Seal of the Canal Zone and a profile of a stylized modern jet-powered airliner. The Seal dates back to 1904, when it was first authorized by the Isthmian Canal Commission. Its actual design and manufacture was accomplished by the famous firm of Tiffany & Co. in 1906. In 1965 the Isthmus of Panama was served by both Braniff and Pan American airlines, and collectors presume the stylized jet represents one of their DC-8s or 707s.
Each of the stamps in this twelve-stamp series except the 80-cent represents a specific postal rate, and students of modern postal history assert they are a delight to collect.
The numbers printed vary tremendously, reflecting their expected and actual use. By the time the Canal Zone Postal Service (CZPS) ceased operations at close of business on Sept 30, 1979, all of the low values still in stock and many of the higher values had been snapped up. In fact, only the 6-cent and 8-cent were destroyed in fairly large numbers when they were no longer needed, long before September 1979. The last remnants of the CZPS stock were burned in 1980, and over 1,100,000 of these were 20-cent to 80-cent airmails from this series.
The Canal Zone Seal and Jet airmails are all found on first day covers serviced by a variety of people. Due to public demand, the 10-, 11-, and 13-cent stamps were also made up into booklet panes to provide a convenient way to store stamps. In the realm of postal history, the possibilities are nearly endless, which accounts for their popularity. While the low values are quite common on cover, when used in combination with other stamps to meet 'odd-ball' rates, they are in particular demand by specialists.