The Advanced Tactical Laser (ATL) is a directed energy weapon (aka ray gun) developed by Boeing under a US military contract. According to an overview document (PDF) about Boeing's Directed Energy Systems program, "In August 2009, the ATL defeated a ground vehicle target from the air, demonstrating its first air-to-ground, high-power laser engagement of a tactically representative target." The video above documents that experiment, in which the laser weapon, mounted on a C-130H Hercules transport plane, was fired at a car. See the Boeing site for more videos, including aerial footage. (via Smithsonian Air & Space)