If I wanted to fly out of Thailand to a neighboring country and then return back would the airline require me to have an onward flight out of Thailand? I know they are required to check if you are flying on a one way ticket without a visa from your own country but not sure if the same rule applies with neighboring countries. My tourist visa will expire soon and I might need to stay for only another month or two so I don't want to apply for a new one. Also, can anyone confirm if I will be able to switch passports (from another nationality) on that flight as my current one is near full and the other one is empty? I want to have the option of doing a border run instead of a flight.

I think I know the answers but just want it confirmed from anyone who has done it or knows for sure. Thank you.

Ticket is not normally required on an area flight but if you do not know your plans why not stay one day and get a tourist visa? That would allow up to 60 plus 30 days if your stay turns out to be longer than expected with no need for border crossings. Yes you can change passports on air travel.

Ya you are right, maybe I will fly into Laos and then apply for a tourist visa on the other passport.