I got back from Thailand this week and I had zero issues in and out of the airports. I had the drone in my carry-on and they didn't ask to look at it a single time. They asked to see my batteries once, but it wasn't a problem bc they are under the size limit and I had the terminals protected.
I only flew my drone on the beaches in Krabi (we stayed on Railay Beach), but here are the cities we went through airports in: Dallas, Seoul, Chiang Mai, Bangkok, Krabi, and then back through Bangkok, Seoul, DFW. No one asked me if I had it registered with the Thai government, but I probably would have if I had time.
No one stopped me on the beach while flying it. Too bad it was pretty hazy, the footage is just ok. I went to the least busy spots on the beach, and stayed pretty high so no one noticed. Some of the popular beaches (like James Bond Island) have signs posted 'no drones', but it was so packed I wouldn't have wanted to anyway. I hope this helps.