Bowies generally have a wider blade than a fighter, but without knowing what knives you're talking about we can only talk general stuff. The bowie might be a little stouter to hold up to camp chores as well, but that all depends on the maker.
Blade length really doesn't come into play at all. I've seen short bowies and some long ones. Same with fighters. The 'newer' styled fighers with their extreme curves in the handle aren't too useful as true fighers (or general use), so it's an interesting development. They look cool, but I'd take a single-edged baselard, rondel or seax with a basic handle over them in a fight any day.