Let's review a few sentences with some of the common means of transportation in Spanish speaking countries:

Los aviones de la aerolínea son grandes.
     The airline airplanes are big.
A ellas les gustan los carros.
     They like cars.
Rodolfo maneja el autobús.
     Rodolfo drives the bus.

Note that the preposition en is regularly placed when referring to traveling, just as we use "by":
Yo di la vuelta al mundo en avioneta.
     I traveled around the world by light aircraft.
Los alumnos van a la escuela en carro.
     The students go to school by car.
Voy al colegio en autobús.
     I go to school by bus.
Ella prefiere que vayamos en tren.
     She prefers to go by train.
Fuimos en bicicleta a Friburgo.
     We went to Friburgo by bicycle.

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