I keep my usa phone only for 2FA. My international phone I have 12 different sim cards for all the countries I travel to just this year. It’s not the best way to go but for now it works having two phones
at 18yo I know its hard to let go but the quality of life for your pet should be your priority and flying around the world without stability for your pet is in my opinion something you should consider finding a family too care of him at least until you are completely settled into a home.
yes every airport requires it even on a layover and its best to submit the paperwork within the 6wk timeframe or within a month. Best to call the airport customs I’ve had a few approved and never got a response emailed
if you’re traveling to multiple countries just make sure you’re pet is allowed in the country before hand there are a lot of countries that won’t let your pet in no matter how much you pay them. Unless they are a service dog.
I have flown with air serbia Turkish Airlines and American Airlines and affiliates. I would suggest flying business class at least because it is a long flight and most overseas airports don’t have a potty palace in the airport so check. There are a few airports but it depends which direction you will travel east or west. Cinder lasted 14hrs but had to get authorised escort from Taiwan on one of our trips we have travelled to 8 countries around the world