This actually happens.
The problem with planes is somewhat *too much* simulation.
Spring planes kind of actually simulate lift from the wings being dependent on speed and angle of attack.
But because those same planes move at velocities that are much lower relative to their body size than actual planes, for them to work they have to either be very light, or for the air to be very dense.
Both of these result in very high friction when the plane's propulsion kicks out, almost - almost! sufficient to stop it. If you look closely at an emp-paralyzed plane in ZK you will notice that it actually falls; just that it does so very slowly.
It is plausible that there's some hack that would allow planes to keep moving slightly faster when paralyzed, for proper physical hilarity, and could be done game side. Most likely though this would require some kind of an engine change.