Peer into the future of aviation as Fly Past features craft like the stealthy, robotic Unmanned Combat Air Vehicle and a solar-powered flyer designed to stay aloft for months at a time! The 4th and final episode, "The Cutting Edge", explores future developments in aviation such as stealth technology, hypersonic flight, lifting bodies, solar power, remotely-piloted vehicles, and mini-spy-planes no bigger than an insect. A glimpse at the future of flight technology, including the stealth-like Unmanned Combat Aerial Vehicles (UCAV's); Mini-UAV's (Unmanned Aerial Vehicles), tiny 8-inch long vehicles that fly to equip special forces behind enemy lines; solar powered aircraft designed to stay aloft for months; and the X-planes from X-32/X-35 JSF Joint Strike Fighter concepts to X-43 hypersonic test vehicle.