If you want the ultimate over-the-air surveillance gadget, you might want to build a hexacopter, like a helicopter but about 10 times more stable and can go straight up or down like a UFO.

video://www.youtube.com/watch?v=fyYujjP5J-k

I would really like to see a bigger, life-sized version of this and travel, seems like the 6-copters are ideal for doing some crazy maneuvers in air.

The author of hexacopter has put a nice set of instructions you can follow to build a hexacopter here.

Thanks to Josh for the tip!