Originally Posted by
kt74
QR and TG do interline, but I've not had success getting QR to check through bags on separate tickets (YMMV)
PG will definitely check through bags and issue boarding passes on separate tickets on your way back, and in fact they're set up to do so. I suspect TG is the same, but be careful not to book the Thai Smile-operated flights, as they operate like a quasi LCC (only interline to Thai)
There are no arrival lounges at BKK for any airline. If you fly PG to HKT, you can use their Y class departure lounge, but it's just a waiting room with free soft drinks and slow wifi - no showers if that's what you were after
PG=Bangkok Airways
TG=Thai Airways
And yeah, I forgot to say that, the other way around TG will most likely check the bags all the way for you. Have done with success in the past, on separate tickets. But remember this is not something the airline/check-in agent is required to do for you, so ask nicely for it