BoardingBlue17" x 13" x 8" Airlines Free Personal Item Backapck, Black Backpack fits Spirit,America Airlines, Jetblue, Frontier. Backpack Size: 17" x 13" x 8" One back strap (A bag can be strapped on top of another carry on) Friendly Reminder: Please Do NOT Pack Too Much. Or It may cause the bag oversized. It is also the size as a free carry on for most of the airlines