Aircraft
by Nation
United States
Navy/Marine Corps (1923 - 1962)
Transport: The U.S.
Navy started using "R" for Transport (T already being used for
Torpedo aircraft) in 1931. The use of the designation "G"
for single engine transports was short lived and was only used in the late
1930s and early 1940s. The "JR" designation for Utility
Transport was also used from 1939 to 1954 when it was replaced by
the "U" for Utility
designation.