A month later, the Post Office issued its first Air Letter Sheet, which also picture the SkyMaster. The smaller size was adopted in preparation for future issues that could be used as coils or booklets and sold in vending machines. On March 26, 1947, the SkyMaster design appeared on a new, smaller airmail stamp. US #C33 – first SkyMaster stamp issued at the smaller size The Post Office also reported an increase of 19 million airmail letters sent in the first two weeks of October compared to the first two weeks of September, which they credited to the new lower rate. The SkyMaster issue was soon known as the “Nickel Air Mail Stamp” and was promoted during National Air Mail Week. The stamp and a matching Airmail Stationery Envelope were issued on September 25, but the rate didn’t take effect until October 1. This was a savings of up to 90¢ per ounce.

This included airmail sent to and from US territories including Hawaii, Guam, and the Canal Zone. The first SkyMaster stamp was issued in 1946 to pay the reduced rate of domestic airmail from 8¢ per ounce to 5¢ per ounce. US #C32 – first SkyMaster stamp, issued in the larger format The SkyMaster was also widely used in commercial aviation and to deliver airmail. The aircraft quickly played a critical role in the Allied war effort and the Berlin Airlift of 1948-49. The DC-4 SkyMaster made its maiden flight on February 14, 1942. Only a few more coil stamps would be issued over the next 30 years, but the DC-4 SkyMaster would appear on more than a dozen postal items. The first US Airmail coil stamp was issued on January 15, 1948, in Washington, DC. US #C37 – America’s first Airmail coil stamp

Airmail 5 cent plane stamp value