The U.S. Marine Corps is testing a pocket-sized drone that can deliver live video feeds from three cameras and is small enough that it's almost invisible from the ground. The Black Hornet PD-100 can stay aloft for 25 minutes and has a range of 1.6 km (1 mile). That means Marines can use it for surveillance far beyond their current position. It can fly missions guided by GPS yet fits in a pocket. The cable hanging out the back in this image is an antenna, not a cord for power or data.