Welcome to YorkieTalk.
I have not had experience with yorkies on transatlantic flights. My little sweetie, just 17-1/2 weeks old, was born in Missouri. She has an international pedigree as both her mama and papa came from different parts of Eastern Europe. Little Dutch (Duchess) is AKC her parents have dual registrations.
Here's the link to AKC's "
Special Registry Services." Scroll down on that page to find AKC's list of "Foreign and Domestic Registries." There is a listing in
Ukraine.
It sounds as though you are on a great adventure. I wish you the best. --KatysMom.