What are the requirements for traveling by air with a dog?

I am traveling one way to Memphis Tennessee from Ontario Airport. My dog is approximately 80 lbs. and 16 years old. What do airlines require?

I think only Alaska transports live animal. I know most dont do it only cabin pets verify before buying ticket!!!!!!

check your airline's website. At minimum, health certificate not more than 10 days old, crate big enough for dog to stand up & turn around in. When you add the dog to your reservation, make sure to give crate size, to be sure it'll fit!