Wow, that's sure going to be a long trip for the cats. Just to note, cats don't have to go in the cargo hold. When I fly, I always have my cat(s) with me in the cabin, I would never ever let them go in the cargo hold. It doesn't cost much extra and you know they are safe. A car ride seems like it would take too long. My cats have passports and all. Little international flying felines, they are.