Ground shadows are activated in your setup screen. . . ."Cast Shadows". . . ."Receive Shadows". You have to check what objects apply!
Just to clarify, I'm using V3.2.2, NVidia GTX 650 Ti, 2Gig, Driver Ver. 365.10. I have no problems with shadowing either inside or outside of the airplane. Also, my lighting section is actually set exactly like "ejoiner" with the exception of the "Dynamic Reflections", I have that unchecked.