Eli5: How come flies don’t smash into the back window inside a moving vehicle while they’re flying around? Surely they don’t fly “with” the vehicle.

Question

Eli5: How come flies don’t smash into the back window inside a moving vehicle while they’re flying around? Surely they don’t fly “with” the vehicle.

In: Physics

Answer 1

The air is vehicle is moving with the vehicle so the fly just needs to fly *almost* normal.
When accelerating from a stop the air does ‘slosh’ to the back of the vehicle until it equalizes, you can observe this when you have helium balloons because they will come forward towards the windshield during acceleration.