They should be fine in check in or carry on. When I was checking in people for Mex and Carib flights, families would check in whole coolers. Your hairspray, shampoo and other toiletries that are liquids don't explode, so why would your non-carbonated juice boxes? They won't. Even carbonated beverages make it through check-in just fine. We always pack sodas for cruises, so I've btdt. So, if it's easier, you can put a few in the carry on to use as you travel and store the rest in check-in. Since they aren't cans, I'd put them in a plastic tub or shoe box before packing to keep them from getting crushed. Actually, I have done that with juice boxes and snacks now that I think of it. It worked beautifully.