Being of Dutch heritage, I have an opinion on everything, and being me, I have a bit of experience in many things, but never an expert.....
On the one hand it alarms me that the focus of control on drone incursions to airports is fanciful notions of "drone-guns" whatever they are. Great, let's add to the complexity of flight by adding teams of gung-ho people with some sort of weapon that can damage things flying near an airport - airplanes anyone??
On the other hand, this focus is probably media driven and fostered by armchair warriors.
I will share my very limited experience and knowledge here, just so it may add to the discussion.
I operate a drone. A DJI Phantom. A fairly common model, typical of the mid/upper end of privately owned/operated such machines. It weighs a couple of kilos, is almost built entirely of plastic, with just the battery being a fairly solid chunk - a few hundred grammes and about the size of two Mars Bars strapped together. I severely doubt that the impact of such on an airliner would be much more severe than a large hail stone, or a crow. Even though I know such a collision would not be ideal.
But the main thing I wish to share is how I perceive the main thrust of drone-control in restricted airspace is actually being managed. Just like an iphone or any other modern piece of technology, the manufacturers manage to maintain much control via mandatory "updates". In the case of my drone, if I do not do these updates the drone simply ceases to be flyable. What they have worked in here, in a way I respect and admire, is that hidden amongst the updates is a system where DJI is hard-blocking the use of the drone in identified restricted airspace.
The way this works is simple - the drone has GPS, it has electronically programmed barriers of where it will not fly. If I tried to set up and send it into an airport it would hit that electronic fence, and no matter what I tried to do, it will not fly closer/higher/lower than the limits specified by the manufacturer.
This is how they are really battling the problem.
I suspect that the smaller the drone, the lower the software requirements, and thus the easier it is to use or hack to get into restricted airspace. But likewise the potential danger a tiny drone poses gets smaller and smaller.