I completely agree. But for mass market personal aerial vehicles, regulation would eventually force vehicles to fly close to ground (for safety of self and others, better fall 30 feet than 300 feet)
In this scenario, geodesic distance hardly makes any difference.
Personal aerial vehicles are never going to be safe. Not for the lack of innovation or technology, but for human nature. Ever see how many people drive their cars with the "check engine" lights on? Or how many fail to get theirs serviced in time, or change the oil in time? The mass market is not fit to drive their own personal aerial vehicles.
There are niche uses, such as medical emergencies, policing, etc. Putting these into the hands of everyone is a disaster waiting to happen.