At first, I look at the Funone and where it talks about rearranging the seating. And specifically how a Troll driver would need the seat in the middle. So it makes me think the 2/1 means either 2 normal sized folks, or 1 Troll.
But more and more, I'm suspecting that was intended to reflect extra space specifically for hauling cargo. For instance, the Universal Hovercraft Minnesota is described as a cargo craft with a cabin for 2 and extra cargo space. Which would explain the 2/12 listing. The Nissan Hauler has 4/4 which if we were talking about reconfiguring seating, makes no sense. But the fluff text does talk a lot about having plenty of cargo room. Since the Core book does say that you can either haul X people, or 250lbs of cargo per seat you fill with stuff... maybe these are saying that it's got room for 4 passengers, and 4 "seats" worth of dedicated cargo space otherwise unfit for passengers