The FAA isn’t the only government body worried about the harm that small drones could cause. On Thursday, the Defense Advanced Research Projects Agency, or DARPA, released a request for information for new measures to defeat small UAVs, which, they say, are “creating new asymmetric threats for warfighters.”

Small “UASs’ size and low cost enable novel concepts of employment, which present challenges to our current defense systems,” according to the request.

DARPA is looking for technology to “detect, identify, track, and neutralize these systems on the move, on a compressed timeline, and while mitigating collateral damage and providing flexibility to operations in multiple mission environments.”

More than a few technologies exist to counter drone threats, but jamming can pose a threat to nearby electrical and computer equipment. One of the more interesting solutions so far comes out of Japan where Tokyo police are deploying drones armed with nets to capture other drones.

By itself, most small drones don’t pose a great danger but they can easily be modified with a variety of payloads. Pro-Russian forces fighting in Ukraine use drones to spot and target enemy positions. Last August, a group of hackers at DEF CON unveiled a small garage-built drone that flies around looking for vulnerabilities in computer networks.

Isreali Aerospace Industries markets something that they call a multi-rotor loitering munition for ground forces, basically a quadcopter with a bomb strapped to it that hovers in the air until the operator decides to kill someone with it. Hamas and Hezbollah’s use of small drones goes back to 2004. ISIS, too, is experimenting with small intelligence drones (and possibly armed ones as well). In July, the Pentagon switched $20 million toward a new anti-drone effort.

Any drone under 55 lbs is considered small by FAA standards. The agency projects that more than seven million small UAVs could cloud America’s skies by the year 2020. The development community for small drones is also growing rapidly, bolstered by trends in 3D printing and tiny off-the-shelf computer systems like the Raspberry Pi. Anybody with an internet connection can create their own drone at minimal cost. As large as seven million sounds, the figure might be woefully conservative.