This little glider, called the Micro Air Vehicle, is being developed by MIT as a possible surveillance tool. For such a small craft, though, big batteries are pretty much out of the question. I’m not sure exactly what they’re planning on powering, since it’s a glider, but I’m going to go ahead and defer to MIT on that point. In any case, if it has any power draw, it can’t work for long without big batteries that would make it difficult to fly. MIT engineers decided to have it replenish its power supply in the field by going straight to the source: power lines.
The glider basically swoops in and lets the computer control take over as it approaches the cable. A plane that light would be difficult to control by hand, especially during a stalling maneuver, but the computer does it right, ending by settling itself on the power lines with a little hook.
They seem mighty vulnerable in this position, though — like a bat sleeping. There’s more than one benefit of going back to HQ, after all. At HQ you don’t have people shooting at you.