Other forms: stowaways
A person who hides on a vehicle to get a free ride is a stowaway. If your cat sneaks into the back seat of your car and travels to school with you, she's a stowaway too!
The verb phrase stow away came first, meaning "conceal," from stow, or "stash." By the 1840s, stowaway was being used as a noun to mean "clandestine traveler." Anyone who sneaks onto a boat, plane, or train and hides out during the trip, stowing themselves someplace secluded, can be described as a stowaway.