I flew my 12 week old borzoi pup up from Tampa - when the big cargo door opened there she was, sitting up in the crate saying "HERE I AM!!!!!!". I swear nothing fazes this dog.
At the zoo, we'd fly animals all the time cargo - animals with much higher stress levels than domestic dogs, and in my 14 years I don't ever recall a negative incident.
If you fly them, be sure to follow the directions about proper crating, crate identification, and securing the crate. It wouldn't hurt to have the pup microchipped ahead of the flight as well, but honestly, an 8 week pup isn't running too fast too far if it gets loose (which, yes, happens, it makes the news, but it's pretty rare).
That being said, I'm personally driving down to Missouri to pick up my new Borzoi pup in person on Friday
(it's cheaper than flying him, actually)
Bicycling is the number one reason for the increase in the ranks of reckless girls who become outcast women" ....unknown 1895