Quadrotors are great, but what kind of range can you get on them, really? What if you could charge them up just by flying over high voltage power lines, by or temporarily hovering by a charging station? That’s just what [Dr. Carrick Detweiler] wrote a paper about! (Caution: PDF)
The paper discusses the method of wireless power transfer via magnetic resonance, which, depending on the scale, can transfer power at medium distances (~1 meter). This outperforms inductive coupling which requires a much closer proximity (~1-2 centimeters) for power to transfer. It does still require a certain amount of accuracy, but as we all know, quadrotors have no problem with even the most complex aerodynamic feats!
There is an excellent demonstration video of a small scale wireless quadrotor prototype after the break.