ventilation
hi I have a MacBook Air almost new, since I have done the update macOS Big Sur every time I watch a movie or an episode of a series the ventilation systems goes crazy, its really loud and doesn't stop.
MacBook Air
Your Air should be on a hard surface with sufficient room around it for adequate ventilation. The fan will still spin up for movies, but at least you are doing all you can to help it manage thermal gain from prolonged GPU usage.