Question

¿Sabe usted a qué hora sale el próximo __________ para Madrid? No quiero perderlo

Answer 1

Tren

It is most likely train because spain is known for common transport by trains. Considering that it asks "qué hora sale el próximo" (when the next one comes) it probably isn't talking about a plane.

Answer 2

Answer:

Autobus o tren

Explanation:En algunos paises se utilizan esas dos palabras (in some countries they utilize those two words, but it depends)

hope this helps :)