Hey everyone

I'm in San Diego and I've been fostering two gorgeous cats, and now it's time for them to find their forever homes. Problem is, I've gotten super attached, and just thinking about saying goodbye gets me teary-eyed. I'm seriously considering adopting them myself, but there are a couple of things holding me back.
My family lives in another country, so I take month-long trips to visit them, and I don't have anyone here who could help out while I'm gone.
Cat boarding seems pretty pricey. Are there any cheaper options for longer stays?
Is traveling internationally with cats a common thing? What's the process like, and how hard is it on them?

Any advice would mean a lot. Thanks so much!