passenger
A person riding in a vehicle but not driving it.
A passenger is someone who travels in a vehicle but isn't controlling it. When you ride in your family's car, you're a passenger while your parent drives. On a school bus, every student is a passenger, and the bus driver is in charge of getting everyone safely to school.
Throughout history, people have been passengers on ships crossing oceans, passengers on trains connecting cities, and now passengers on airplanes flying between continents.
Passengers often wear seatbelts, avoid distracting the driver, and may help watch for hazards when appropriate. On longer trips, passengers might help navigate, choose music, or help the driver stay alert.
The opposite of a passenger is the operator or driver, the person actively controlling the vehicle and responsible for everyone's safety.