We had quite a bit of discussion on skycars around the week of August 20; check the archives. Our aerodynamics experts seemed to think the concept was sound in theory but there was some skepticism that the current Moller design would work as described.
My biggest concern was the concept that the cars would fly themselves, with some kind of computerized air traffic control system. This is putting a lot of trust into software, which as history shows tends to be an unreliable technology.
Even if the skycars could take off and land without producing so much wind and noise as to be unbearable, you'd have problems in parking lots or if two cars tried to take off and land near each other, due to air wake problems. Airplanes have to be as lightweight as possible, which means that they are strongly affected by winds. You'd have to tie the planes down somehow (or clamp them) if they were all close together, and you'd have to coordinate so that two nearby planes were never leaving at the same time, part of the general ATC problem.
If you are going to have to drive to the airport to fly them, they don't make sense. Just get a light plane. The big selling point is the VTOL and the point of that is you can take off and land anywhere. This is what causes all the problems with traffic control.
Hal