This is a wonderful backpack. The hard frame measures 21.5 inches according to my measurements, so therefore, I assume that if you do not stuff it full, it will fit carry on measurements, but please check with your airline before flying. Very comfy, It stops being very comfortable after around 25lb for me but it possibly can work with some adjustments. For me, the reasons to get this is that it has a lockable compared to backpacking packs that have many openings, making them susceptible to pickpockets, and that it will fit carry on dimensions if not packed full and if the compression straps are used. The other Fairviews do not come close in terms of the quality of their suspension and are not good for people who will walk/trek with their packs during travels, in my opinion.