Individually, these drones can't do much damage, but as a swarm they are hard to defend against. They can carry explosives or electronic jammers capable of knocking out a radar system or other sensors. This is the plan for LOCUST, the US Navy's low-cost, swarming technology, which has just been revealed in Pentagon documents.

A highly secretive Pentagon organization is experimenting with'micro-drones' which could one day take to the sky like a like a swarm of robotic locusts. The experiments led by the Strategic Capabilities Office were conducted in Alaska last summer, according to The Washington Post, during which the tiny drones were launched from fighter jets. After launch, the 3-D printed micro-drones break free of a canister and seek each other out to create a swarm. The micro-drones have inch-wide propellers, and can be launched from the flare dispensers of F-16 and F/A-18 fighter jets. After launch, they descend in a parachute-equipped canister and then break free.