Answer:
I save lives on the ground and in the air. What am I?
I am easy to see but no one likes looking at me. Without me there would be no you. I can make you complain or make you happy. But you almost always take me for-granted.
I jump when I walk and sit when I stand.
I come in different colors and shapes. Some parts of me are curvy some are straight. You can put me anywhere you like but there is only one right place for me.
You have to travel far before you turn it over. What is it?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.