Unfortunetly it took legislative action in 2000 to correct what really was going on with transporting animals in cargo of airlines. Over 5000 animals were either killed or injured traveling in cargo. If you would like to read the actual legislation with the FTA then go to the following website and then in the seach type animal travel. This is a PDF file that is to large for me to post on YT.
http://www.animallaw.info/statutes/stmodelanimalact.htm
I cannot tell you how many animals died flying into AZ during the summer months because of the heat. They were treated the same as luggage
Now I believe there are 4 months (hottest times of the year) airlines cannot take the animals as cargo. This only changed because of legislation and not because the airlines cared.
Personally, I am opposed to shipping of puppies for alot of reasons but I will keep those thoughts to myself.