Since no one else seems to be anxious to start the guessing game, I'll give it a shot. Two candidates come to mind pretty quickly, although neither really meets all the clues. Ot at least, I don't think they do. Still, here goes. Thanks; Ernie P.
The Lockheed Model 12 Electra Junior, more commonly known as the Lockheed 12 or L-12, is an eight-seat, six-passenger all-metal twin-engine transport aircraft of the late 1930s designed for use by small airlines, companies, and wealthy private individuals. A scaled-down version of the
Lockheed Model 10 Electra, the Lockheed 12 was not popular as an airliner but was widely used as a corporate and government transport. Several were also used for testing new aviation technologies. Connection to the P-38? Well, Kelly Johnson helped develop the Model 10 and the P-38. Developed specifically as a trainer? Not that I'm aware.
The Beechcraft Model 18, or "Twin Beech", as it was better known, is a 6-11 place, twin-engine, low-wing, conventional-gear aircraft that was manufactured by the Beech Aircraft Corporation of Wichita, Kansas. This model saw military service during and after World War II in a number of versions including the United States Army Air Forces (USAAF) C-45 Expeditor, AT-7 Navigator, AT-11 Kansan; and for the United States Navy (USN), UC-45J Navigator and the SNB-1 Kansan. An estimated aggregate total time in service for the aircraft is in excess of 20,000,000 hours.
Role: Trainer & Utility aircraft
National origin: United States
Manufacturer: Beech Aircraft Corporation
First flight: 15 January 1937
Introduced: 1937
Primary users: United States Army, United States Navy, Royal Air Force
Produced: 1937-1970
Number built: More than 9,000 of 32 variants built
Unit cost 1952: D18S $78,050.00 USD
Connection to the P-38? None, that I'm aware.