No explanation. I can only speculate that perhaps those are to keep other vehicles at a distance to prevent parking lot road rash.
I can not make out any wheels. Could these be a wheel substitute?
Please let us know when you find out more.
Im pretty sure they are actually props using the same concept that tugboats use... the Voith Schneider propeller (VSP)...=wing incidance is +12 deg. ,and -30 degreas flaps for take off...
-I was asking about small car modell with strange rotors autside wheels.
Voith Schneider Propeller - Wikipedia, the free encyclopedia
His simply retract into the hubs. Not a bad idea, but it can be simplified.