Question: Why is it when a fly is in a lift it doesn't it hit the roof when the lift goes down?

Nadine Mirza answered on 12 Nov 2018:

In short- when the lift goes down the fly feels the force of the lift moving downwards. in the same way the fly would also notice the ceiling coming towards it. in this instance the fly would rapidly stop moving its wings enough to allow gravity to move it down, but would exert enough force with it’s wings to keep it in relatively the same place within the lift. flies can manage a lot of complicated movement with their wings.
this explains it quite excellently: https://www.thenakedscientists.com/articles/questions/how-does-fly-fly-elevator