"The tourist gets onto a boat, and not onto a car."
Translation:A turista egy hajóra ül fel, nem pedig egy autóra.
I would probably not say "felül" with a ship/boat, nevertheless it is okay. But neither "felül" nor "felszáll" are correct with "autó". And "autóra" itself is already weird. Unless you sit on top of the car.
Therefore I would say this sentence differently.
"A turista egy hajóra ül, nem pedig (egy) autóba." Or: "A turista hajóval megy, nem pedig autóval." Or: " A turista egy hajóra ül fel, nem pedig autóba száll. " Etc.
The point is, I would use a verb that can be used with both vehicles, or use two separate verbs.
why not put egy hajora in focus and use ul fel? Isnt the focus here that they are getting on BOATS not cars
Usually you would contrast it like that, but there's nothing against saying "A turista felül a hajóra és nem az autóra", just counting down what the tourist does and doesn't do, without putting special emphasis on it.
But this sentence is a mess anyway. ._.