Tunnels indeed would be good. But I understand there the problem is scale. It's not so easy to make a large amount of small tunnels for traffic? (They are possible for piping though for some reason). But easier to make one big tunnel.
For drones, it's the opposite, they are very well suited for very small point to point connection, there is basically no infrastructure needed between the points whatsoever?
Right. There’s no infrastructure needed, just already existing infrastructure like power lines, telephone poles, radio towers, buildings, gusts of wind, signs, etc.
Yes they don’t need infrastructure, but there is a cost to using the air. The risk that your drone fails and harms someone, someone’s property, or even just the drone itself.
Plus the additional risk that you get banned from using this airspace.
For drones, it's the opposite, they are very well suited for very small point to point connection, there is basically no infrastructure needed between the points whatsoever?