If birdstrikes can bring down a passenger plane (remember "Sully"?) what do you think a hobbyist drone would do to an aircraft engine?
We have the technology to prevent that, and it would be criminally negligent to delay implementation of systems to protect our planes and people. Airports have radar monitoring of their column or airspace. It's probably not accurate enough to find a small hobbyist drone, so it needs to be improved. Once they are identified, the airports need lasers or laser-focused electro-magnetic pulses strong enough to disable a hobbyist drone. These weapons wouldn't be strong enough to hurt a plane (or even a military drone), but could prevent a dumb or malicious hobbyist.