Noticed So mething on a bus............?

Question

I took a bus today and I noticed a fly moving back and forth on the bus. I’m not sure how fast a fly can go but wouldn't it be difficult for it to do that. The bus was going about 35 miles per hour.
How do you explain that?
Seeing as though the speed of the bus isn't being transferred to the fly.
Just musing

Answer 1

The air inside the bus, if the bus is closed, moves with the bus itself. Next time you should take a bus with air conditioning.

Answer 2

The air the fly was flying in was also moving at 35mph. If it wasn't, you would have noticed a 35 mph wind while the bus was in motion.

Answer 3

Everything in the bus, including the air and the fly in the air, is travelling at 35mph relative to stationary objects outside the bus.
If the fly is travelling at 1mph forward in the bus he's travelling at 36mph relative to outside but only 1mph relative to inside.
Flying to the back of the bus it's flying at 34 mph relative to outside but still at 1 mph relative to inside..

Answer 4

Open a window, and the fly won't be able to go against the wind.