A ordinary hanger will provide protection against a homemade/civilian based drone attack if the bay door is closed. It does mean that you need a protection team in place when bay doors are open and aircraft are being moved. Protecting the fighters will be easier than the larger aircraft. You may have to build "net tents" that the aircraft can fit under. Likely incorporated in with protective berms. Permanent jammers in place that can be switched on and off as needed and optical trackers. Which will no doubt cue onto every fricking bird that goes by. Hopefully energy weapons will become reliable enough to be used near urban areas to avoid falling shrapnel. A couple of dudes with shotguns on duty with a truck mounted optical tracker is also required to escort aircraft as they move or hangers/nets are open.
For airfields not in urban areas, but near non-military structures (ruralish) I have to think that 20mm gives you some reach, but with a smaller safety zone for falling shells/debris, for airfields closers to other structures, a smaller caliber. The internet gives me a danger zone of a 20mm at roughly 6.5km. So for Comox, you would have to stick to 5.56 or 7.62 and you need gunners well trained to avoid shooting your own buildings, antennas, etc.