DARPA has said it wants a 10-gram aircraft with a 7.5-centimetre wingspan that can explore caves and other hiding places, relaying GPS data and images to base. It will need to fly at 10 metres per second and withstand 2.5-metre-per-second gusts of wind.

Aeronvironment has released video that shows its "nano air vehicle" (NAV), which is the size of a small bird or large insect, hovering indoors without such crutches and under radio control. "It is capable of climbing and descending vertically, flying sideways left and right, as well as forward and backward, under remote control," says the company.

http://www.newscientist.com/article/dn17608-hover-no-bother-for-flapping-nano-aircraft.html