I'd think best combat would be via radio intercept and interference with their base, unless programmed to independently fly, which is unusual.
Back in my days of employment, I worked with a couple of individuals who were pretty big into drones.
Most of the 'heavy-duty' ones had smarts built into them so they could 'fly home' to a given lat/long point where the flight originated.
One individual in particular was getting HD resolution video from his from two or three miles out. The device would sense a certain battery level, then would go into 'fly home' mode...only taking a few minutes, apparently.
So, if the drones that are creating aviation hazards to flights with humans, how much radio power - and on what frequencies - are you going to jam that signal?