[cmurf]

ADS-B is effectively to replace Mode C. There's nothing in the mandate that expands Mode C required airspace. So that leaves a metric ton of space not covered by the rule for conventional airplanes, let alone drones. Drones of course need a totally different and scalable system.

Something possibly like a centralized flight plan, that's given an ack/nack/patch, and then the drone flies that plan on its own without needing constant comm like today's aircraft do (more like IFR plans where you're expected to complete the entire cleared flight plan, to the minute, in a comm failure). And then all drones share all flight plans that affect their routing. And all nearby drones rat each other out if any drone deviates from their flight plane. That'll scale. ADS-B may not.