Flyinside is a (paid) add-on to base FSX or Prepare3D that allows you to use an Oculus Rift and hand-tracking Leap Motion to fly within a VR environment.
This video best explains it:
The ‘in-flight’ desktop is neat and the hand-tracking helps with all the worries about needing physical cockpits with VR.
With the release of Oculus CV1 and HTC Vive ‘soon’ this might be a glimpse of how a lot us might be flying over the next couple of years.