If from DMK airport take Thai Lion Air to chiangmai, will I met with the great jam of China (tourist)? I am flying from Singapore to DMK airport and boarding the next flight to Chiangmai. How many hrs apart should I book my chiangmai ticket?
Are both your flights with Thai Lion Air?
If so, you will be given a ICQ sticker when you check in at Changi Airport. When you reach DMK, all passengers with the ICQ stickers (meaning they have a domestic connecting flight) will be led by a staff to an immigration counter within the transit area.
After clearing the immigration, you can only stay within the transit area to wait for your connecting flight.
Your luggage will go direct from Changi to Chiang Mai. No need to collect and re-check in at DMK.
Even if your flights are on different airlines, no harm asking when you check in at Changi.