A very serious threat on the field of combat and as a terror weapon. We need to counter this threat. The military has countermeasures but it is only a matter of time when we see the era of drone terrorism.
And, in the US itself (or any overseas base) a series of small drones will be used to destroy squadrons of USAF planes. Takes very little explosive mass to damage a wing or engine.
They’re are already numerous private sector companies producing anti-drone systems:
http://www.dronedefense.systems
The problem is the development curve. For every defense there is a countermeasure that is usually easier to produce. We are fast approaching Skynet type technology to use a poor trope. The military swarms offer some pretty terrifying capabilities. In a few years, it will be like being thrown out naked in the Alaskan Bush to be killed by a million mosquitoes.
Everyone should check out this mockumentary:
https://m.youtube.com/watch?v=fWzXjn5hHjs
It’s not real, but it’s already out of date from a tech standpoint.
And that field of combat is going to be the streets of the US.