It sounds like you're expecting VR to make a difference to the landscape or such. If you're in a flying plane, everything outside the plane is so far away that you don't get any depth information from stereoscopy. VR could be nice for the cockpit and takeoff/landing, but it doesn't seem essential.
There's more to immersion than stereoscopy. All the different elements of VR (3DOF tracking, positional tracking, 360 imaging, hand/controller tracking, stereoscopy) work together to flip a switch in your brain that tells it that you are in something rather than merely looking at something.
Even simply covering the entirely of your 360 range of view is enormous on it's own for flight sims. Think of the $$$ that sim enthusiasts spend on multi-monitor setups.
VR makes a big difference if you don't have one of these crazy multi-screen setups. It is not about depth perception, more like just being able to look at your sides naturally.
The advantage is in being able to move your head to see more than what is directly head of you.
Maybe they could do something like how in Elite Dangerous you hold middle mouse button(? can't remember exactly what the control is) to freelook, but that's not as good as being able to control your PoV directly by moving your head.
