Flying cars - the most cliched artifact that a near future fiction could use. I could digest drone-like propeller aircraft (it is imaginable that in 2077 they have very powerful batteries) but vehicles flying by the way of magic is a big divorce from reality. Just a mindless use of a cliche. Yep, I know, the whole environment of the game is a cliche, but at least they could have cut the most rough edges.

As far as I understand following the original pen and paper RPG is the whole idea of the game. This is not a scientific prediction of the future in the sense of Stanisław Lem’s futurogical/philosophical essays, but a future with a good dose of the rule of cool, zeerust, and other tropes. That’s half the fun.

You must consider the fact that there is some special technology under the hood of those cars that can't be seen from the outside. Most UFO's/ancient "vihmannah" (probably spelled incorrectly) vehicles have all kinds of really weird technology that allows them very strange lift/propulsion properties without any engine exhaust or visible exterior moving parts. The engine interacts with the space around the vehicle from inside of the vehicle through strange forces we don't understand. Also, the game is supposed to be FUN. Style is an unusually important part of the structural integrity of an experience. Imagine a drink that's lost its fizz. No fun! "But that fizz is unrealistic!" YES, that's the point! People play video games to escape this boring normal world. Cool eh?

Not too early for hate? Game didn't release yet, and You know already what You don't like. Feel free to create product that EVERYBODY IN THE WORLD will like. It is like in grocery store, You go and buy what You like, if You don't like anything there, go to different shop, not come to the clerk saying how You would run the shop. You've expressed opinion, You're entitled to that, so I'll express mine: Nobody Cares! Now go troll elsewhere.

Actually, the real problems with flying cars (in a setting close to 50 years from now) are more practical than technical. As you say, sufficient portable power sources are not entirely implausible, and with sufficient power you could build a flying car using vertical thrust from relatively compact jet engines. Look at articles about personal air vehicles on Wikipedia (and follow the sources). This would not necessarily mean visible fiery exhaust jets under the car, but there would definitely be a noticeable downdraft (e.g. any nearby loose objects near / under a low flying air car would be blown away).

The practical problems - regulatory, driver skill/training, traffic management, public safety, etc. - would be another matter, at least insofar as "flying car" implies vehicles meant to be driven anywhere at any time (no having to file a flight plan, restriction to approved airports or heliports, etc.), particularly at low altitude in and around cities, and typically by drivers/pilots with no more training or licensing requirements than your typical (ground) car driver. Cyberpunk 2077 seems to be assuming a setting where the regulatory and public safety situation is (at least locally) far more lax than it is in most present-day developed countries, but that only exacerbates the the driver skill issue. The driver skill issue could be reduced by relying heavily on autopilot, AI driver assist, automatic collision avoidance, networked traffic mnagement, etc. However, if these features are easy to bypass or turn off, vast number of overconfident idiot drivers who really shoudn't do so inevitably will, because people are like that, with disastrous results.

Conversely, if these systems are not easily to disable, then the flying cars are reduced to flying taxis (i.e. not really controlled by the "driver" beyond entering a destination). That might be fine for the ordinary citizen, but it makes chases, dogfights, fly-by shootings and similar forms of excitement generally impossible. Special unrestricted models might be available to police and government types, but not for (most) private citizens, and any unauthorized aircar operating "off the rails" would be immediately assumed criminal (partly for the licence violation, mostly for suspicion that they must be up to no good). And on the mean streets of cyberpunk dystopia, that could very quickly lead to getting blown out of the sky or having about 50 cop cars hot on your tail.

But it really isn't that far fetched you know? It's just secret/hidden/lost ancient/alien tech and it's absolutely real but the public has no access yet.

If you though accidents in nc are bad on the ground, just imagine the size of the police force needed to control air cars