[KazzyK810]

I've flown to France and then took the ferry to England a few times with my last yorkie, as that was the only way to have her with me during times of seasonal temperature extremes, and not have to travel in cargo.

I don't think you'll be able to fly with her as a pet as she wont have had her rabies shot and all her puppy shots by that age. And they are very strict on the pet passport about rabies. She will also need to microchipped with the international chip.