Re: Flying taxis = wrong solution to right problem
"One big impediment to Personal Rapid Transit systems so far has been the lack of an autopilot that allows the PRT pods to travel quickly"
Which PRT implementation are you looking at? UltraPRT (may be gone now) built the system at Heathrow terminal 5. Not a big system, but it navigates itself. There is also a system under Masdar City in Dubai (I think it's Dubai).
PRT seems like an excellent fit for dense city centers. So far no council has wanted to take the risk as it's "unproven" so they keep buying busses and letting taxis do the point to point work. So much for progress. On the flip side you get places like Las Vegas that are happy to let Elon burrow sewer sized tunnels under the convention center for a system that doesn't look like it will ever be viable.
The cost of ground based transportation ranges in cost from surface roads to elevated roads to underground "roads". In a city like London, the surface is full up. The Underground is great for throughput efficiency but doesn't cover the last mile very well. An obvious solution is an elevated road system that uses automated lightweight electric pods with less capacity each but more possible stops. They could even route through buildings as they don't emit pollution being electric. Ultra PRT was exploring an option for people to own their own pod so they could drive to the edge of a city, log into the elevated guideway and the vehicle would self drive to the destination and then be sent on to a parking area to wait until it was called.