> RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. And there's been some effort to have autopilots do it auto

> RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. And there's been some effort to have autopilots do it automatically https://ardupilot.org/plane/docs/soaring.html https://ardupilot.org/plane/docs/soaring.html