Just a data point on domestic air travel.
Travelled BKK -> UTH on Thai Smile Airways. Check in was fairly normal, with just a document check to ensure I am fully vaccinated. Paper CDC card accepted easily.
No service during the flight...food or beverage. When deplaning, a "to-go" bag was distributed. For Smile+ (prem econ), it was a chicken curry pastry, a fruit pastry, and a bottle of water. Economy received a smaller bag, but I don't know the contents.
A document check was also made after retrieving luggage and before exiting into UTH airport. Passport + CDC card was all that was needed.
Overall, quick and easy process. No mention of any tracking app / check in / Morchana whatever during any of the process.