I live near a major airport and see commercial planes with huge front headlights shining in the night sky. What could they be good for way up in the sky, though? I get that when they are taking off/landing headlights are necessary. Why not give them lights like a boat, with a green in front and a red in back?
The big white light is used for landing.
Moreover, while it’s not legally required, most airliner would turn it on when changing altitude, in order to improve other planes siftuational awarness
(I was curious when visiting family living on a hill with a view on the airport down the valley)