Answer:
I have feathers that help me fly; with head and body but I'm not alive. Very skinny and a fixed length how far I go depends on your strength.
I only exist when you are here. Where you never were I can never be.
When you are inside me you will be encouraged to slam other cars.
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it, can't see it. What is it?
I am the building with the most number of stories.
What never asks questions but receives a lot of answers?