I do have to wonder exactly how they intend to have several of these navigating a closed circuit together. Aside from the obvious problem of the vehicle not touching the ground, meaning track limits like kerbs and gravel traps are effectively pointless, there's also the matter of safety. Inevitably you're going to have two or more of them bumping into each other for various reasons, and rotor-driven aircraft aren't exactly fond of being suddenly jostled about. (Well no aircraft is really, but still.)
I suppose you could have a bunch of sensors and computer assists to enforce track limits and try to avoid contact, but then why even bother having a pilot? They may as well just be car-sized drones at that point.