I don't know that contact is required. It could be as simple as notifying the aircraft which can likely out fly any drone given sufficient warning. Alternatively, a reverse ping from the aircraft could freeze the drone for 10-15 seconds to allow the aircraft more time to react.
To me, the issue (long term) isn't how to accommodate civil aviation. There are just over half a million civil licensed pilots flying roughly half that many planes. It won't be long until the number of drones and drone pilots massively dwarf either of those numbers, if they don't already. Going forward, once businesses figure out how to incorporate drones and get the necessary approvals, it is civil pilots and craft that will be expected to bend over backwards to accommodate UAS vehicles. Outrageous? One sector will drive or be closely related to a large percent of GDP. The other, a hobby for a few rich guys.
I truly appreciate any interesting and unique suggestions, because sometime, somewhere, someone is going to come up with something that will work, or be the basis of a greater plan.
I don’t think you’re at all wrong that the drone industry has the potential to dwarf civil aviation, but more than that... even if those in power refuse to accept that they will have to accommodate hobby craft, the emerging technology of airborne personal transport craft WILL have its day to be respected as well.