Rail lines go all over the country but they check when you cross even if that’s not your destination. I would expect the same to be true here: e.g. an airship l

Rail lines go all over the country but they check when you cross even if that’s not your destination. I would expect the same to be true here: e.g. an airship leaving Mexico would go to, say, Riverside via a customs stop in San Diego or Calexico.