I flew into Chiang Mai straight after I landed in Bangkok (rookie mistake), because I was already flying for 20 hours. This was not counting the layovers. Had no time to rest adn as a result I ended flying for 24 hours in total (because of the time difference) but honestly it felt like 40 hours. I should have stayed in Bangkok as my first stop and then go to Chiang Mai but now I know for next time. Advice- think about your route twice.
Flight from Bangkok to Chiang Mai (two way) with Thai Vietjet Air 56.95 USD