. . .thrust the opposite way would require that they slow down stop then reverse direction.
I doubt the mechanism CIG uses posits fixed blades, nor even blades at all. The Prowler doesn't have blades. It has grav plates.
One simple observation would be to see if there is any negative thrust setting for any given ship, but really the only empirical way to know is to try to fly a ship upside down, under the hover mode velocity. If it instantly falls to the ground, then hover does not work inverted.
Given we don't know what equations they used nor the parameters for them, the only way to know is to try--which will likely get you killed. Better now than when beta comes.
Whether any given ship is able to set a negative thrust for hover is TBD. Best case is not all ships are the same. It will be exciting to find out. Certainly, if you have a Cutlass, a Tally, a Gladiator, a SH, a Vanguard, a Hurricane, or any other ship with dorsal turret(s), you need to know whether you can hover inverted.
I highly suggest die trying now, while it doesn't matter.