They're not on the bus.
4 seconds sound clip from the Beavis and Butt-Head Do America movie soundboard.
You can hear this line at 00:35:57 in the DVD version of the movie.
Quote context
[...]
- This is the coolest thing I have ever seen.
- Chief, we got 'em. They're on a bus on Highway 89.
- Ah... heh... yeah, that was great.
- Yeah.
- Uhh... is this the right bus? Um... heh heh. Uh huh huh huh.
- Hey, Beavis, we're on a bus with chicks. Hey, baby.
- These people know something. I want full cavity searches. Everyone. Go deep on 'em.
- I tell you, Bork, these guys are smart, damn smart. They're probably a hundred miles away by now.
- Cool.
- Check it out, Butt-head - porta-potties.
[...]