I found some posts from 2007, however a lot may have changed since covid. I called united airlines, whose one-way price is now twice the roundtrip price pre-covid. They say they’ll take cats as long is there is not more than 5 total non-human animals on each segment of the flight. The cats must be in carriers (hxlxw) either hard 7.5"x17.5"x12" or soft 11"x18"x111" to carry on board. Clearly soft-shell is needed. The carrier counts as an exception to the carry-on allowance, so 1 carry-on, 1 carrier, and 1 personal item.
They no longer put critters in the hold (since covid).
If anyone knows:
Is there no cat-quarantine going into the US (I think there isn’t)?
They only need a rabies shot and English letter saying they’ve had it?
They need to be chipped to leave Taiwan?
Where is the best place in Taipei to find the biggest allowed soft-shell carrier?
Anything I’m not thinking of?
Pee pads in the soft shell. If you can find a cheap zippered cloth pouch about the size of the carrier foot print, get some Cat’s Best clumping litter. That stuff is miraculous. Not the universal, but the smart pellet, or the granules.
If they pee during the god knows how many hours of travel you’ll have, the pads will still stink. So litter, or bring a spare if you sniff them out, toss the old one in a barf bag.
As far as returning to the US with pets, the biggest issue is likely just a current rabies vacc. I don’t think chipping will be necessary, but if you have a known vet in the US, they may suggest a standard or type of chip. I don’t think anyone would want to have to chip their Gatos twice,…, not after you see the size of that needle. In other words, chipping is a good idea, but make sure it’s a chip type that is usable state side
I don’t think you would be able to leave without a microchip in the cats.
Don’t worry about two chips.
Both of my pets have two chips. One had stopped working. And the other had the US preferred chip and I needed a UK/EU preferred one in case there was no reader for the US preferred chip at immigration (which would have resulted in delay while I could have incurred payment to have one brought to the airport).
Talk to Yang Ming vets (who deal with procedures exporting pets) in TianMu.
They will know what you need to do for travel to the USA.
If the cats are going in the hold (you may use another carrier), do not give them sedatives.
There are reports online of death of animals in the hold on sedatives.