So overall, turning off the lights during takeoff and landing is a necessary measure to improve visibility and safety for pilots, ATC controllers and passengers. It is an important part of the safety protocols that help ensure air travel is as safe as possible.

Airlines dim or turn off cabin lights during takeoff and landing (especially at night) primarily for passenger safety and vision adjustment. In the event of an emergency evacuation, it is critical that passengers' eyes are already adjusted to the low-light conditions outside the aircraft. If the cabin were brightly lit and the power suddenly failed or an evacuation was required into the darkness, passengers would be temporarily "blinded" while their pupils took several minutes to dilate, wasting life-saving seconds. Furthermore, dimming the lights makes the illuminated emergency exit signs and floor-level path lighting much easier to see through smoke or debris. It also allows flight attendants and passengers to better assess exterior hazards, such as fire or engine issues, through the windows without being hindered by the glare of interior lights on the glass.