In 1949, the Air Force conducted initial testing with a little known experiment to evaluate wing tip coupling with a Douglas C-47 Skytrain and a Culver Q-14 Cadet at the Wright Air Development Center at Wright Field in Ohio. Theory predicted that increasing the aspect ratio of an airplane wing by attaching another wing at its tip improved aerodynamic efficiency, offsetting the drag of the smaller plane. A bomber would be able to tow a fighter into a combat zone with little loss of range.
As expected, this idea proved to be highly dangerous, and even more so once experimentation began with larger and faster aircraft.
The biggest problem was the extreme vortex that was generated at the wingtips of the EB-29A, which caused the attached parasites to roll violently. The entire three-plane EF-84B/EB-29A/EF-84B array crashed as a unit on April 24, 1953, killing all the crewmembers. The project was terminated shortly thereafter.