Very cool drones, many of them new, being built or in development around the
world. These are some amazing aircraft, ranging from a 150-gram thing with a
single maple-leaf-like wing, up to some monsters with 175-foot wingspan that
carry a boatload of munitions and sensors. Power ranges from fuel-cell
electric power to a modified Ford truck engine that burns hydrogen:

http://www.popsci.com/technology/gal...-future-drones

--
Ed Huntress