Khon Kaen is poised to become the first international gateway to the Northeast when Thai AirAsia (TAA) establishes an overseas link.
The low-cost carrier plans to embark on regular flights between the province known as the regional centre for education, financial institutions and state offices, and Kunming in southern China early next year.
The route launch, announced by TAA chief executive Tassapon Bijleved, will directly reconnect Khon Kaen with the outside world after a short-lived connection between the province and Luang Prabang in Laos.
Private carrier Lao Central Airlines offered flights between Khon Kaen and Luang Prabang in 2015 before ceasing operations.
Plans are also afoot for TAA to establish an additional domestic regional route linking Khon Kaen with Phuket by the year-end, according to Mr Tassapon.
TAA has the most flight connections with Khon Kaen: four flights a day from Bangkok's Don Mueang airport and one a day each from Chiang Mai and Hat Yai.
Other airlines serving Khon Kaen are Nok Air and THAI Smile, both from Don Mueang, and Kan Air from Chiang Mai.
TAA's planned Khon Kaen-Kunming route follows a renewed bid to turn the province into an international gateway for the region.
It also comes on the heels of the 2.5-billion-baht upgrade of the airport that will more than double its annual passenger-handling capacity to 5 million from 2 million at present.
The upgrade, slated for completion in 2020, will see the passenger terminal space expanded to 50,000 square metres from the current 15,000 sq m and the apron doubled to accommodate 10 aircraft the size of A320 and B737 jets, airport director Athaya Larpmak told the Bangkok Post.
But there is no plan to extend the runway, now at 3,050m, which is capable of handling wide-body jets.
Passenger traffic through Khon Kaen has been leaping due to the province's importance as a centre for meetings, incentives, conventions and exhibitions that cater to universities and government agencies, which host events year-round.
Business and leisure traffic have also contributed to the rise.
Passenger throughput soared from 900,000 in 2014 to 1.28 million in 2015 and 1.5 million are expected this year.
Mr Tassapon did not provide details of the planned launch of the Khon Kaen-Kunming route, which raised a few eyebrows among industry experts as Khon Kaen has not been popular as a destination among Chinese tourists.