Last year, DARPA granted aerospace firm, Aeronvironment, a chunk of change and six-months to demonstrate a bird-sized Nano Air Vehicle (NAV). This video shows the result: the "smallest ever free-flying aircraft to hover and climb with flapping wings".
The image above comes from Aeronvironment, and shows what it wants the prototype in the video below to ultimately look like. DARPA's goal is to have a 10-gram aircraft with a 7.5cm wingspan. They want it to get into tight hiding spaces and send back GPS and image data.
Aeronvironment's progress is also notable because such robots previously couldn't carry their own batteries, and had to use guide wires.
"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.