The Twelve-cent Prexie
Double airmail use
The domestic airmail rate was six cents per half ounce from July 1, 1934 until March 26, 1944.
The cover shown above was sent at twice the domestic airmail rate in 1940.
From December 25, 1941 until October 1, 1946, U.S. service personnel serving abroad could send airmail letters to the mainland for six cents per half ounce.
The cover above was sent from the Naval Supply Depot at Balboa, Canal Zone to New York in 1944 at double the military concession rate.
Domestic airmail rates were again six cents per half ounce from January 1, 1949 until August 1, 1958. This double-weight airmail letter was sent from San Juan, Puerto Rico to New York in 1957. After October 1, 1946, airmail rates to, from and between U.S. territories and possessions were the same as the domestic rate.