I purchased this carryon bag so I wouldn't be forced to check my bag on a full flight. It definitely fits all airline regulations.This was for a three day weekend in NYC. I admit I didn't put under seat but it would have fit(but not likely with my larger purse under there).I put my liquids and small make up bag in my purse because with what I put in my bag they would not fit. I packed my iphone charger, an smaller messenger purse for walking around NYC, a pair of jeans, a pair of pants, 3 long sleeve tops, 2 turtlenecks, 1 cardigan sweater, 4 pairs of socks, a pair of yoga pants and a t-shirt as well as underwear/bras for 3 days. It all fit without difficulty. I could not have put another pair of shoes in it but I planned to wear the same pair with all outfits. If you are not a light packer this will not be for you, but I had plenty of extra tops etc in case of mishaps and didn't have to use. I really liked it. The comment my brother-in-law made when he picked me up was"that's the smallest carryon bag I've ever seen!", but it really worked for me