I am in a tricky situation and did not find an suitable answer online yet, so hopefully somebody here can help me. Next week I will fly from Austria to Thailand/Bangkok (BKK) with OS (Austrian Airlines). In Bangkok I will continue my journey to Chiang Mai (CNX) with a domestic flight. To keep it simple, I would like to check-through my luggage from Austria directly to CNX. But here it gets tricky: I booked the domestic flight on "Thai Airways International" webpage, so the domestic flight has the flight number TGxxxx. Luggage check-through should be possible here, because Austrian Airlines and Thai Airways are both participants of Star Alliance. But now I discovered, that my flight from BKK-CNX is operated by Thai Smile, the pocket discounter of Thai Airways, so my domestic flight is a code-shared flight. As far as I know, Austrian Airlines does not have an agreement with Thai Smile to check-through my luggage. Am I still able to check-through my luggage to CNX, because I do have a TG-flight number? Also, do I need to online check in at Thai Airways or Thai Smile? (I read already that one should check-in at the flight operators webpage which would be Thai Smile, but all the data I have from my booking suits for Thai Airways webpage and not Thai Smile webpage)
Thank you very much for your replies. Best regards, Stefan