Lockheed TP-38J Lightning This aircraft was unofficially designated TP-38J to identify a certain modification. These aircaft had a small seat for a second pilot behind the original seat, and was used for conversion training, or for training for the P-38M night-fighter crews
Number converted: unknown
Lockheed TP-38L Lightning Two aircraft were converted to conversion trainers with a second seat
Number converted: 2
http://www.xs4all.nl/~fbonne/warbirds/ww2htmls/lockp38.html