I agree, air taxis seem like pie in the sky at this point. There was a helicopter ferry to LaGuardia called
New York Airways. I could see that being revived. It has a pretty good excuse for closing though, one day a chopper failed to land and the blades slashed 4 people to death before falling 59 stories and crushing one more!
I think I'll try some simple calculations on the feasibility of a slow fly quad. The gearboxes might be too heavy, I'm imagining the rotors would spin slower than the propeller on a fixed wing. I wonder if a ringed rotor could be used as a pully speed reducer.