[ listen... she is a seventeen year old with a much more limited perspective on the real life mortal world, thanks to all the time she spends at a camp for demigods. and she spends a lot of time in new york city, where a car isn't even always necessary! maybe they ARE junk. maybe they're not. but it's her only vehicular comparison. ]

That makes sense. I guess in my head I hear 'spaceship' and I just assume it can travel across space - but different cultures and worlds would adapt to transport with variety, especially if space travel is an influence already.