Not all **MacBook Air** devices have this feature of automatically lighting their keyboards. From my observations, newer MacBook Air devices, those from 2018 and later, have this feature where their keyboards are backlit and change their level of brightness according to their surroundings, thanks to their ambient light sensors, which work well in dimly lit environments. However, older MacBook Air devices may not have this feature or may have it but cannot change their level of brightness automatically. Yes, most newer MacBook Air devices support this, but this depends on the MacBook Air device you are using.