This depends on the design, helicopters are not a great way way of getting around due to their size and how they are controlled, so the infrastructure for them becomes a problem, eg you couldn't have a multi-level parking station like we have for cars. But a car like those in the 5th Element, suddenly they are very practical and could have similar parking stations where you just fly into each level.
Part of the point here is that the design is the problem. There is simply no way to get around that the energy needed to keep an object that is heavier than the air up in the air is vastly, vastly greater than the energy needed to move things along the ground. Barring magical anti-gravity technology (don't hold your breath), there is no way to make flying conveyances similar to cars and also have them more affordable than cars (except maybe - maybe
The decrease in centralized living space you describe (where we don't need to commute as much, etc.) only makes cars better
- you need fewer roads, they are easier to maintain, and congestion on those roads becomes a thing of the past. You don't need the infinitely scalable nature of the "sky" anymore, save maybe
over long distances, since you can still reach higher speeds up in the sky (and then we're talking about replacing airplanes, and I could certainly see the argument for small, cheap, drone-piloted airplanes replacing large airliners over most flight patterns. But, again, not cars, not privately owned, and not being used in congested airspace).
We are never going to develop a network of privately owned, independently operated flying vehicles that operate in urban areas for the purpose of short-range travel. In other words: the operative definition of a "car" will never apply to any such vehicle. Driving on the ground works just fine and stands to only work better if things decentralize. What we will probably see is delivery drones of some kind and probably more compact helicopters of some fashion, but those will only be used for commercial or government purposes, as I said above, since they'll either be too small to be of use as a vehicle or too expensive to own.
The only instance in which flying cars make any degree of sense is in an environment in which travel along the ground is impossible or so impractical to make forcing an object like that up in the air easier
than just building and maintaining a road. So, exclusively vertical environments or places where the terrain and/or weather is so hazardous that road maintenance is completely impractical. If we want flying cars, then, we're going to have to look to establishing cloud-colonies on Venus first.