This sounds like a very good idea, but there are some problems. The wash from such a vehicle would exceed what could be reasonably allowed in an urban setting. Failure of an engine would cause unimaginable damage to property and persons. A parachute could not be reasonable backup because of the constant low altitude that is desired. The lack of vertipads means having to drive to an airport, takeoff, fly to an airport near the destination, then drive to the destination.