> The flights were given a cover story, describing the drones as high-altitude targets for surface-to-air missiles (SAMs), in case one of them came down in a pu

> The flights were given a cover story, describing the drones as high-altitude targets for surface-to-air missiles (SAMs), in case one of them came down in a public area. > The system injected chlorosulfonic acid into the engine tailpipe when the drone entered hostile territory, which created very tiny ice crystals, forming a transparent contrail.