Physicist: This question has had a lot of forms, from questions about hot air balloons, to “just hovering in the air”, to weather. But the common thread boils down to “what keeps the atmosphere moving with the surface of the Earth?”. In physics (reality) there’s no difference between moving and not moving, so a stationary fan is just as good at stopping moving air, as a moving fan is at moving stationary air. Once air is moving with the Earth it’s got momentum, and that’s what keeps it moving (or “what keeps it still”, if you happen to live on Earth). When that east-speed-difference doesn’t get broken down, usually because the air covered the distance too fast, you get a big swirl of air.