What does a solid green light signify at the airfield?

A solid green light at the airfield is a clear signal for pilots, indicating that they are cleared for takeoff. This signal ensures that the aircraft has received the necessary clearance from air traffic control or the control tower to proceed onto the active runway and begin its takeoff. The green light provides pilots with visual confirmation of their authorization, which is crucial for maintaining safety and efficiency during ground operations and departures. It is part of a standardized system of light signals that allows flight crews to receive important commands even when communication might be challenging, such as during busy airport operations.