Life in prison
It is only a matter of time before a fatal accident results. Hopefully the culprit will be found and charged with capital murder for committing a felony that results in death. That one example will make other hobbyists decide to stay well away from planes, I'll bet.
The real problem isn't the hobbyist though it is the terrorist. Why mess around with trying to smuggle a bomb onto a plane to bring it down? Simply fly a drone into the engine intake on a twin engine jet on approach and I suspect the results would not be good, and the terrorist would have much less risk and live to do it again. Airports are going to need the ability to track and bring down (via jamming or something) drones that enter flight paths, especially during landing approach when a "bird strike" can take down the plane.
The first time a terrorist does this, laws will probably be passed that make flying a drone within an airport's airspace a terrorist offense. Send one hobbyist to Gitmo and you'd have the same effect, only problem it won't make the news so no one will learn from his example.