I am torn getting my kitties a hard plastic carrier or a Sherpa bag (I'm afraid they will collape) but United Airlines accepts the Sherpa bags as they fit under the seat.
Not sure what you want help with, but I have the Sherpa bags. The base of them (the part they lay on) keeps the whole thing up and they do not collapse. I like mine, but it's all a matter of preference.
If you are taking the cat in cabin with you and under the seat you need the Sherpa bags. If the cat is flying in cargo under the plane - you need the hard plastic VeriKennel. Some of the cheaper plastic carriers would not withstand cargo areas - they have to be tougher.
When we brought Hypnos home, he traveled in an Argo Petascope by Teafco. It fit the dimensions that the airline required (this is very important), it is airline approved, and it has a double mesh that ensures kitty will not claw his/her way out. A bit pricey but worth it. It is molded, so it doesn't collapse yet it is soft and comfortable. I would recommend this carrier for air travel.
It comes in a small (10lb or less) or a medium size. It's collapseable so you can store it away readily when not in use. When in use, the faux sheep support base keeps it in place with no worry of collapsing.
I do have to admit the Argo Petascope by Teafco looks great. I'm beginning to think of getting one myself. It looks really awesome. How heavy is it?