Is it a school backpack or a larger, hiking backpack?OK sorry again but will they consider a backpack a duffle bag
If it's a school backpack, that's sort of like a purse or laptop bag. We bring one every time, along with two suitcases, a laptop bag, my purse, and a CVS bag full of snacks/alcohol. We've never been hassled, especially since we schlep everything on board ourselves.