which airline is good for dogs?

I have flown 15 dogs on United and 13 on Delta. I have no complaints on either airline.

Do make sure that the airline KNOWS the dogs are coming - you can usually make arrangements to load them and unload them at the passenger terminal - airlines only take a limited amount of live animals each flight. Any dog too big for a carry-on carrier that fits under a seat, fly in the temperature and pressure controlled cargo area. Even though the dog will be in a cargo area, it's still considered a "passenger dog" and will get priority loading and unloading.

It's noisy and traumatic but over in a few hours and they soon get over it.

If at all possible, fly Pet Air. The dogs go in the cabin, not in the cargo hold, and are watched by a "flight attendant" during the whole thing, are cared for at the airport, etc. The dog might still be terrified (I am positive my dog barked the entire flight) but at least you'll know he or she is in good hands. It's a little more expensive than the cargo hold of other airlines, but not by too much. They also only fly to limited cities, but hopefully there's one close to you.

My dog only flies Pet Air, but the airline with the best reputation for animal treatment is Northwest (now part of Delta) though I don't know if they've retained their practices after the merger.

All airlines put them in the cargo area.I have used American Airlines as they handle pets very well.