What weightlessness feels like on Zero-G planes

I would love to know what difference it makes to a VR Headset that it is "accelerating towards the ground".  I mean its an interface between a screen and your eyes.  What does it care if your body is dropping like a rock.  The relative position between the screen and your eye remains constant.  That's like saying that VR Headsets have to be specially programed to work while in a car and calibrated for whatever speed you are going.  Yet thousands of people have tvs in their car for the kids to watch in the back seat.  No special programming was required to compensate for the speed of the vehicle.  The earth is spinning and orbiting the sun.  We also wobble because of the push pull of other celestial objects in out solar system, mainly the moon.  If VR Headsets need some special programming to compensate for how fast you are going I would love to know how they calculated all of those speeds.  Physics explanation please :).. thx