The problem isn't so much gravity as inertia. Hovercraft work great but can't be operated on roadways because there's a lack of positive control (they drift all over the place and can't stop, start, or maneuver quickly).
A flying car has to overcome that problem before it becomes viable as a vehicle that can operate in congested areas or anywhere near neighborhoods, and unlike conventional ground vehicles, no amount of parked cars, curbs, berms, trees, and a stone foundation will keep an out-of-control flying car from crashing into your bedroom at 60 mph, and crashes will
happen due to unforeseeable circumstances (falling trees, unsecured loads flying back off a truck, teens tossing things out a window, etc).
You could possibly overcome these problems by having the car latch itself to a magnetic track, which could be stacked into almost any configuration (like a giant fence you'd see around a horse farm). That would give you a car that could operate normally or
stick itself to the wall and be supported from the side, a simple variation on the idea of a car that followed tracks in the roadway.
As they say, at speed your car only contacts the road with four patches of rubber about the size of your tongue. If you want to eliminate the roadway, all you really need is to focus on is controlling what those four patches touch, or their equivalent.