Since I’ve only flown my dogs with American Airlines as cargo, I can’t say why it’s different from another airline except for things I’ve heard. I flew them to BA in 2014. I chose American because they had a direct flight from Dallas to BA and I didn’t want my dogs to be in the air any longer than possible. Customer service at Dallas-Fort Worth as well as customer service at the BA airport were all great. I had no problems but I understand other people occasionally do.