I see the advantages of a hardside carrier (no one can smush it) but I like the softside carriers I use with my cats. They have zippers all over so you can zip open just enough for your hand to fit in and pet the little guy. One of my cats is likely to mew the whole flight if I don't have my hand in there patting his head. That means I'm leaning over almost the whole flight so that I can keep my hand in there, but he's worth it.