A Hitchhiker
A hitchhiker is a space traveler who doesn’t have a spaceship. They ride with other people’s cars and hope no one kills them.
Arthur Dent is a hitchhiker who got stuck on Earth after a planet was destroyed. He didn’t like it much.
Ford Prefect is a hitchhiker who travels the universe with a towel. He knows where it is.
Zaphod Beeblebrox is not a hitchhiker because he has a stolen spaceship. He’s just a thief.