The largest suitcase is too big to take on an airplane without an additional $100.00 charge (United Airlines). The actual size empty is 31 x 12 x 20+. (The airlines include the wheels in the measurement.) Even if it was within the size limit, it would be too heavy and there would be an additional charge for that. I used the medium suitcase and it was still over the 50 lbs allotted. If you don't plan to use it to fly, it's a great set of luggage (if you can lift the biggest one).