FreeCamera is a simple mod that decouples the camera rotation from the vehicle. It allows the camera to keep its orientation while vehicles are turning.
Freecamera mode toggles through a new entry-binding (default Ctrl + V). The mode is saved and switched separately for each vehicle, for the internal and external views. Modes will persist for each view in which it is set, and this setting will be remembered when you view them again.
(Please note that the camera states are not saved to file and will not persist across game sessions)