I haven't... I wouldn't... too many sweet puppies close by (and we don't need fixed features, so we're more flexible on "sourcing" issues).
I'd be happy to drive a day or two to get just the right puppy, versus flying them in. Too many unknowns happen in flight.
My old boss had a "doodle" flown in from Australia (supposed home of the original "doodle") to Seattle. That puppy was fine and dandy once he was cleaned up and home (he had a lay-over in LAX where they gave him a bath before the last leg). I don't think he had any lasting issues. He was a happy, friendly dog, all his life.
With today's understaffed and underpaid personnel working the airlines, and all the dogs that have been lost or died while in their care... I'd still avoid it if at all possible.
If you do fly one in - be sure NOT to do it in the hot summer, or cold winter months... too much chance that crate will be left on the tarmac somewhere in bad weather.
We flew with our 5yr old 190lb mutt (GSD/Rott/Pyrn) cross country... one 6 hour non-stop flight, plus an hour ahead and time to get him from baggage claim. He was never the same. He used to love sleeping in his crate. He never wanted to go back in after that. I think it was too small for him for that long, even though he regularly slept in it for longer than the flight, and we gave him some sleepy-pills for the flight, too. Puppies should be much more resilient, though.