The Eighteen-cent Prexie
Airmail special delivery
There were two periods when airmail special delivery letters cost eighteen cents. The first was when domestic airmail cost eight cents and special delivery cost ten cents, from March 26, 1944 through October 31 of that year.
This airmail special delivery cover was sent from New York to Salt Lake City in July of 1944.
Domestic airmail cost five cents from October 1, 1946 until January 1, 1949. Special delivery cost thirteen cents during that period.
This special delivery cover was sent airmail from California to Michigan in 1948.