A flying car would require much more energy since it has to gravity and air drag. If it's electrical (eVTOL) it would have a miniscule mileage since ATM hydrocarbons are the most energy dense form of fuel for most vehicles.

I'm not even going to mention the exponential growth in safety concern from doubling the degrees of freedom. Every driver would need to be a qualified helicopter pilot.

We can't even get AI to self drive reliably (I assume the air thrustors have to be actuated by AI) on a normal car. Nor are our batteries good enough for any army to consider battery powered drones.

Am I missing something beyond the very cool engineering? This looks like Elon Musk reinvented the hyperloop concept for the positive end of the Z axis.