The challenge of interoperability in controlled airspace is difficult when trying to integrate autonomous & pilotless vehicles (I.e. UAV/RPV/Drone) with aircraft being flown in conjunction with ATC. For a moment, consider an alternate future....with manned & unmanned aircraft all under computer control. Road trials of driverless cars have proved so far that it's the cars with drivers that cause collisions and so it's easier for all vehicles to be automated. Extend that concept to 3D aviation....
Oh no! Our jobs! Our pensions!
LTP