A revolution in on-demand air transportation services for persons and property is on the horizon. Developing out of small, unmanned (drone) aircraft now being utilized extensively for various kinds of aerial survey operations, a race is under way to develop larger vehicles (eventually all-electric vertical takeoff and landing (eVTOL) aircraft that will piloted initially but eventually will be unmanned and autonomous) that will be able to actually move people and goods point-to-point at low altitudes and over relatively short distances in highly congested areas, for example from urban high-rises to local airports or for the delivery of goods directly to peoples' front doors. (A broad range of websites tracking this activity abounds—see, for example: https://transportup.com).