Anybody who thinks that using current propulsion systems (propellers, jets, rockets, etc.) as a viable technology for a levitating air (or space) vehicle is honking the clueless pipe, in my opinion. As you mentioned, high fuel consumption is big disadvantage. Also, they still would have to land and take off in designated areas for questions of safety and health (nobody wants to breathe all that dust and exhaust fumes). Piloting an air car is, by its nature, a dangerous proposition. So much so, that any personal air car that is not 100% self-piloting is out of the question for mass adoption. This would increase the cost exponentially. In the end, you would end up with an expensive, dangerous and fairly useless contraption. Eventually, you realize that the best you can do is no better than something that is already here: the helicopter.
But who says air car dreamers are forever stuck with a dangerous and crippling beast fastened to their backs? Who says that current propellant-based propulsion systems are all there is? Imagine if we had a transportation technology that made it possible to travel from Earth to Mars in hours or from New York City to Beijing in minutes. You may think this is impossible but, in that case, the air car will remain an eternal dream and space colonization and exploitation will forever remain primitive and overly expensive and dangerous.
The space propulsion and ground and air transportation industries must look beyond their current understanding of physics if they are to come out of the rut they are stuck in. It's obvious that current physics is not going to solve this problem anytime soon. Physicists must retrace their steps and reevaluate their fundamental assumptions and practices to uncover a solution.
Our understanding of motion is a case in point. Every physicist seems to be under the impression that inertial motion is uncaused; two bodies in relative motion remain in motion for no reason, as if by magic. But what if this is not true? What if Aristotle was right about the causality of motion? What if there is something (some form of energy) in the "vacuum" that acts as a causal substrate for motion? My point is that a correct and complete understanding of the true nature of motion would, without a doubt, uncover new avenues of research that would revolutionize transportation. NASA and Darpa should promote as many fringe avenues of research as possible, in my opinion, regardless of their expected payoffs. Nobody is going to win the lotto if nobody buys a ticket.