Thought. The drones usually know their location by onboard GPS. The “grown up” aircraft too. What about something like ACAS? If it is in the airspace, it should broadcast its position (and what I call “intent” - the direction/speed, where it wants to be in a moment, and “envelope” - the steering ability, where it could be if needed in a moment, and how much clear space it needs around).
All drones then receive this data, and automatically get out of the way if something heads at them.
The get-out-of-the-air-entirely approach is unsustainable; the cost of airspace access dropped to rock bottom and the benefits are too high. Autonomous agents negotiating for the airspace are a more viable way.
