I struggle as much as the anyone with imagining the leap required for these urban mobility concepts. I can say that industry in the US and NASA have committed significant resources to solve the challenge. One step forward was taken two weeks ago when the FAA accepted (not approved) the certificate application for SureFly, a first of its kind aerial vehicle with potential urban mobility applications. Another challenge is the below 1000ft AGL altitude Class B/C/D/E and Class G airspace world will need a new paradigm for rule making and its own ANSP (air navigation services provider) to address separation and flow control.
SureFly | Workhorse