My bet is something like a large scale RC plane with no real time video link. The tech is already here: 1. Gas engine would allow for >1 hour flight times 2.

My bet is something like a large scale RC plane with no real time video link. The tech is already here: 1. Gas engine would allow for >1 hour flight times 2. Flight management systems like Ardupilot means it could have been flying a pre-planned mission with little/no real time control. The helicopter pilots may have been mistaken thinking that it was reacting to them at all. 3. Or maybe it was reacting: two way radio links are nearly trivial with low enough bandwidths. The controllers could have been monitoring the ATC picture and had the RC plane also reporting telemetry. When the police helicopter got close they may have inserted waypoints into the flight path of the RC plane to make it fly away. There are thousands of serious RC hobbyists in the USA alone that could make something like this. Most of them follow the rules, but I wouldn't put it past a drug cartel to pay/coerce someone to make one for them. Maybe foreign spies, but I think that's unlikely considering Davis-Monthan AFB doesn't have any interesting research or test units. The Chinese wouldn't smuggle in a RC plane to watch A-10s or F-16s training in a MOA.