Apologies if this qualifies for the dumbest question award
but here goes.......
When flying the Atlantic on the B777, I have heard the Captain say that we shall be increasing our flight level when we have burnt off some fuel.
What is the connection between going from an initial cruise height to a higher one and fuel weight? I see the obvious connection between weight and getting airborne but don't get the connection from say level 350-390.
Please feel free to award the dunce cap-
Thanks