Hey, did you add your mesh to the scene root? I had the problem when setting up my 6 DOF Pawn that it would move around but the mesh itself would not rotate at all because i forgot that. Literally just a matter of going to the components tab and dragging the mesh component onto the scene root.
Also, for a little more realistic flight behavior i use physics angular velocity.
this little wiki is really good and helpful for flight stuff:
cheers