AeroVironment Nano Hummingbird
The AeroVironment Nano Hummingbird or Nano Air Vehicle (NAV) is a tiny, remote controlled aircraft built to resemble and fly like a hummingbird, developed in the United States by AeroVironment, Inc. to specifications provided by the Defense Advanced Research Projects Agency (DARPA).
Source: Wikipedia — AeroVironment Nano Hummingbird (CC BY-SA 4.0)