Energy used per mass unit
Every time someone starts with "flying cars", I start thinking about energy usage (forget about decapitations, mass accidents and general carnage).
The world is in the middle of an energy crisis. Gas (or petrol depending on where You are) prices are going through the roof.
We have several changes in usual habits - like people avoiding to fly, trains getting more used and so on.
And then we see this: what must be one of the most intensive and less efficient use of energy to move someone from "A" to "B". There must be a market for this, of course. No one said a Ferrari is efficient. But boggles the mind to see people investing all this time and engineering on something like this.
Or maybe I'm just an old grumpy git. Who knows?