The XC-99, serial 43-52436, was a double deck transport variant of the B-36.
It had a considerably larger fuselage, but was never fitted with jet pods.
The wingspan is the same 230 feet (70.10 meters), but the fuselage is 23 feet longer at 185 feet (56.39 meters).
The payload of the XC-99 was 101,000 pounds (45.81 to)
or 400 fully equipped troops. Pan American Airlines ordered fifteen Model 37 twin-deck airliners.
They would have provided capacious restrooms and lounges for their transatlantic passengers.