Earlier quoted context omitted.
Certainly not trivial, and certainly not for $1K. Perhaps in 10 years like the article suggests. However, you could probably take an off-the-shelf large R/C plane or helicopter and put a small explosive payload in it, then crash it into somewhere. Even that would be hard to do for under $1K, and range would be limited.
Good point. I just did some searching around the internet; 20km for under $1k is way off the mark. 300m however with a live video stream and GPS navigation programming is available under $1k even on Amazon: http://lowenddrone.com
Something like:
http://www.steadidrone.eu/octocopter-ei8ht/
Would be a better candidate. Perhaps a small drone could drop an activated payload, but I would forget about launching anything off of them, as that would likely blow the drone out of the sky due to the thrust generated by the payload's propellant.