Earlier quoted context omitted.
Actually, contention for air space wouldn't be that bad. Modern airplanes have a pressure transponder which announces your flight id and the air pressure at your location. From which you can determine a direction, id, and altitude. Create an automated ATC, some simple separation rules (100' vertical, 500' horizontal), and order that drones flying east are on odd multiples of 100', westbound flights on even multiples.…
The thing is, if this idea proves viable, there are going to be (or at least there will be demand for) many orders of magnitude more of these than there are traditional types of air vehicles... And because of the very short range, much of that will probably be in dense urban areas (so it won't be anything like evenly distributed). So... I dunno if traditional approaches to avoiding airspace contention will work so we…
Say you had 5 flight levels each direction, so 10 'levels' in all. Would we have more than an order of magnitude more flight traffic than road traffic? I would argue no.