Suction as I understand it, it had a ground curtain and the blurb talked about the ability to create downforce to keep the roadster version on the road at high speeds.

The same fans that blew downwards to create lift were likely first run to suck it in to the ramp, then reversed.

These demos were not performed by "daily driver" cars - they were multiple look alike props in a magic show, each optimised for the trick shot and not driver comfort or experience (if any driver(s) even took part).