Can I exit Thailand using my Thai passport if I booked my flight with my US passport?

A dual citizen traveling from Thailand can exit the country using their Thai passport, even if their flight is booked under their US passport. The Thai immigration authorities may check that the traveler has a valid US visa when departing, but as long as the Thai passport is presented correctly, there shouldn't be any significant issues. Travelers are advised to carry both passports when departing to avoid complications.