This kit contains parts for two building options. USAF RC-121C, ca. 1955 or the USAF RC-121D, late 1950's
The Lockheed EC-121 Warning Star was an American Airborne early warning and control radar surveillance aircraft operational in the 1950s in both the United States Navy (USN) and United States Air Force (USAF). The USAF version was the RC-121