I'm thinking a flying car is not really viable, at least in urban environments. If you need a multi-mode vehicle then it means that mass transit has somehow failed. It might be different in rural areas but I don't see any rational reason to use the ground mode unless flying is prohibitively more expensive or you have an unusual situation where you cannot fly to the destination.
After the Titan we probably want to to put a lot into of thought into the safety issues. Since there are still cases where the airspace over ground property belongs to the land owner, shooting down a drone flying over your house has no real consequences. There are laws that need to be written or changed or expanded before flying cars are going to be "safe".
If I wanted to make one of these things sky and street legal anyway I'd get the FAA to sign off and then worry about the ground. In some places roads are shared with farm buggies, farm equipment, golf carts, cars, trucks, etc. there is probably an existing niche it could be squeezed into.