Nok Air is set to become the first airline to offer a direct commercial air link between Udon Thani and Ubon Ratchathani starting next month.
The Jan 17 debut of the northeastern city-pair, with three flights a week, represents the airline's move to tap inter-provincial air traffic demand.
Nok Air will deploy a Bombardier Q400 turboprop with 86 seats on the route.
The airline's research shows that many people travel between the two cities, a trip that takes almost six hours by car over a distance of 325 kilometres.
The cities are two of the largest in the Northeast and connection hubs to Laos and Cambodia.
The alternative is inter-city air-conditioned bus service, but private bus companies that operate inter-city services have a poor safety record.
Udon Thani airport is one of Nok Air's operating bases, which will help in opening the new route, said Nok Air chief executive Piya Yodmani.
Nok Air operates direct flights between Bangkok's Don Mueang and Udon Thani with six flights a day and Don Mueang-Ubon Ratchathani with seven flights a day.
With the new Udon Thani-Ubon Ratchathani connection, the airline will be flying to 25 domestic destinations total.
Most of its domestic flights originate from Don Mueang, with only one cross-region route, Chiang Mai-Udon Thani, in service.
Bookings for Udon Thani-Ubon Ratchathani tickets start on Dec 19.