with respect the above is not close to the truth
1. you can buy quadcopter for less than 100 pounds and they will not do all this as above, in fact they are not going to be able to fly at any distance to bother aircraft
2. Drones that you can programme GPS into and they fly themselves are illegal in most countries as you have to have control and line of sight according to the air navigation order. Those that don't come under this are operated by USAF / RAF / A de la air
3. There is a lot of hysteria about this - most chinese RC handsets will not even get to half a mile let alone further.
4. The quads are easy to fly but the orientation issue remains and they are easy to crash. also if the GPS lock is not gained at launch then the GPS is irrelevant
5. In terms of ease of flight quads / prop plane / turbine plane / big heli
Personally - I think this is a lot of scare mongering.... the only major issue is idiots flying these things near people. Plenty of videos on you tube of what big helis do to flesh, image 4 props going like the clappers!!