As mentioned soft sides are fine, but they have to be inclosed can not have an open top. And make sure your fur baby will be able to stand up in it. One of the airline rules. I had gotten a really cute pink one for Phoebe at Petco. It was light weight. I had no problem on American Airlines. I just ordered a Celltei for Annie. I really like what they have done with their carriers. They are spendy but I can already tell you that I will be way happier with the Celltei. You can check their web site at
www.celltei.com
I ordered the pak o pet xs
Good luck and congrats!!!