The 7c Globe and Wing airmail stamp (Scott C28) was issued on August 16, 1958, as part of the five-stamp series reflecting the new postage rates effective on August 1st. Its purpose was to pay for an airmail letter to the United States.
First day covers, usually on envelopes prepared by local cachet artist/producer Elmer Smith, are quite common. There are others produced in the United States especially for the new 7c airmail rate; interestingly, most of these are really intended for the new United States stamp of the same denomination. However, a goodly number were also used for the Canal Zone's 7c Globe and Wing. This stamp is commonly seen on letters to the United States during its period of use, but examples in combination with other stamps are not common.