Lockheed EC 121D Constellation

The EC-121, originally designated RC-121, was a radar-picket version of the U.S. Air Force’s C-121 passenger airplane. The EC-121 provided early warning by detecting and tracking enemy aircraft with the electronic gear in the large radomes above and below its fuselage. The Air Force ordered 82 EC-121s between 1951 and 1955, 72 of which were EC-121Ds. The EC-121 entered service with the Air Defense Command in 1953, flying patrols off the U.S. coasts as an aerial extension of the Distant Early Warning (DEW)