Professor Ilan Kroo has pretty high credibility for whatever it's worth. He led the team that developed the SWIFT glider, which still represents the highest performance for a foot-launched "hang glider". It has a better glide ratio than some enclosed sailplanes and gliders.

Now as for the feasibility of actual, working, reliable, housewife-safe VTOL performance from a flying car, well... Google can afford to waste a little money. At least they didn't give it to Moller