I got this carrier to carrier my two little munchkins. I have a 5 lb yorkie and 8 lb poodle. They fit just fine. So far Ive only carried it on my back as a backpack, and they seem to be alright with it. I love that this carrier comes with two leash holders inside, that way, if I wanted to unzip the top, they still wouldnt be able to get out. I used it in public for 30 minutes and my little yapper (the poodle) was quiet as a mouse! I would definitely reccommend this purchase. I typically fly Southwest, and to me, it seems a bit too big to fly, I hope not though, Im going to give it a go next trip. Great investment if you like to be out and dont want to leave your little loves at home! I suggest getting a little pillow for the bottom though, I find it to be very hard. They seemed fine with it, I just like them to lay on plush things -)