How long do peanut butter sandwiches last at room temperature?

We're going on a long flight with our family tonight. I prepared peanut butter sandwiches for the kids, and would like to pack it already to avoid the last minute rush (or forgetting them). We're not leaving for another 12 hours or so, and it will probably be eaten a few hours after that. (I'm not so concerned about mushy sandwiches because these are little kids, they won't mind.) Bread and peanut butter individually can be stored at room temperature for a significant amount of time... Can I leave my peanut butter sandwiches out for ~15-20 hours?