An anonymous reader writes: The U.S. Navy has unveiled its latest Cicada drone – a smaller model of the smart glider which military scientists have been developing for almost ten years. The tiny autonomous machine was presented last week at the Department of Defense’s Lab Day. The newest iteration of the Cicada, a yellow angular unit with two semi-circular wings, is the smallest and most low-cost yet and is able to fit in the palm of a hand. Cicadas or Covert Autonomous Disposable Aircraft, developed by the Naval Research Laboratory, are designed to be disposable and to work together emulating the insects’ swarm flight patterns. The lightweight gliders are packed with sensors to monitor and feedback data on the weather, temperature, humidity and air pressure. They also offer the option to house microphones or vibration sensors to spy on enemy communications and to detect chemical weapons.