Lethal Micro-Drones that Can Stalk, Crawl and Hover For Days.

The U.S. Air Force is developing agile micro-sized unmanned drones, the size of insects, with 'optic flow' "which will allow remote pilots to fly by 'sight' - rather than flying by GPS, which can be disrupted by buildings or deliberately jammed by enemy forces."

"As the drones fall, they begin to fly - not like planes, but like insects. High frequency flapping wings allow the drones to hover and maneuver in tight spaces.

The military has already produced a drone patterned after a hawk moth that can flap its wings 30 times a second. However, the activity exhausts the drone's tiny battery in just a few minutes, according to National Geographic.

Another drone type soars like a pigeon and perches unobtrusively on a power line to observe a surveillance target with a camera.

The Air Force is working on technology that will allow the drones to steal electricity from power cables and other sources - so they can continue to operate for days or weeks on end."

Great for urban and/or residential environments, right?