The Defense Advanced Research Projects Agency (DARPA) is seeking vendors who would produce viable, low-cost unmanned aerial vehicles that could be launched and recovered by manned aircraft. Nicknamed “Gremlins,” after the fictional good-luck charms used by the Royal Air Force during World War II, the devices would be deployed from C-130 aircraft flying far from harm’s way. The UAVs then would move into hot areas and perform their missions, then fly back to the C-130s for recovery by aircrews. When the C-130s land, the UAVs would be offloaded and re-equipped for their next mission. Each UAV would be good for roughly 20 such missions. DARPA has scheduled a Proposers’ Day for Sept. 24, at the agency’s Arlington, Va., headquarters.