Budget carrier Nok Air highlighted Don Mueang’s reopening with the first flight lifting off at 6am bound for Thailand’s northeastern province of Udon Thani.
Nok Air moved its base to Suvarnabhumi Airport after Don Mueang Airport was flooded.
Two other flights today are to the southern province of Nakhon Si Thammarat and the northeastern province of Ubon Ratchathani.
Overall services of the first day of operation began smoothly, although a minor disruption in communication delayed check-in for 10 minutes.
Passengers appeared to be satisfied with the level of service.
Another low-cost airline, Orient Thai, which also operated at Don Mueang Airport before shifting to Suvarnabhumi Airport because of the flood, has not yet announced whether or not it will resume services at Don Mueang.
Airports of Thailand (AoT) closed Don Mueang airport temporarily on Oct 25, as flood waters flowed onto the runways.
Prime Minister Yingluck Shinawatra on Monday inspected the airport following flood-damage related renovation.
Ms Yingluck said the airport is important as it helps drive the country's economic and cultural development, emphasising that the government sees its importance as on par with that of Suvarnabhumi Airport, Thailand’s gateway airport.
"When Don Mueang Airport was flooded, the government tried to salvage the airport so that it could resume services," the premier said.