Both my dogs were shipped as puppies.
My Boston (now 2) was shipped prior to my getting her. I got her at 11 weeks, but apparently there had been a previous buyer before me who had payed to have her shipped from Ohio to Florida, but failed to pick her up at the airport, and she was shipped back to the breeder. They then found a different placement for her (ie, me).
My Lab pup was shipped to me from his breeder in Louisiana (just outside New Orleans) to Bay Area California, I believe about a 4 hour plane ride. I believe her flew American, as well, but can't remember 100% as the breeder set up all the airline stuff.
While I did not have a bad experience, it is still something I will look to avoid in the future if at all possible. It is a risk, and it is stressful for even a confident pup, even if nothing goes wrong. That said, if I had no way of getting the pup to me by flying in a cabin with it or driving for it, and I felt comfortable with not getting out to see the place the dog came from, then I'd do it again.