While playing around in forge with the gravity volumes I discovered something pretty cool. The ghost and the wraith can drive normaly (as if they were on the ground) on top of the volume block.
Though you need to stack at least two volumes together in order for them to do this, other wise they will not float up to the top. Human vehicles unfortunatly cant do this, for obvious reasons though. Mantis though… that thing still doesnt get off the ground even with several volumes AND several stacked heavy grav lifts lol.