The Department of Airports (DOA) plans to invest more than 24 billion baht to expand facilities at four airports around the country over the next five years.
DOA director-general Darun Saengchai said Wednesday his department is seeking government approval for the budget from fiscal year 2018 onward.
More passenger terminal buildings will be built at Krabi international airport, Nakhon Si Thammarat international airport, Trang airport and Khon Kaen airport, to serve increasing numbers of passengers, he said.
The plan is part of an airport development programme between 2017 and 2026.
The development plan also includes Betong international airport in Yala and Mae Sot airport in Tak province, he said.
While Krabi international airport has a capacity of four million passengers per year, passenger demand is expected to double in the next few years, Mr Darun said.
Nakhon Si Thammarat international airport is able to serve 1.1 million passengers a year. However, the number of passengers arriving at the airport stood at 1.4 million last year, he added.
The expansion is targeted to be able to serve 3-4 million passengers annually, he said.
While Khon Kaen airport has a capacity of two million passengers a year, the number of passengers arriving at the airport was more than one million last year.
The Khon Kaen airport expansion plan will be brought in line with the government's policy of developing the city of Khon Kaen as the northeastern transportation hub.
Work at the three airports is expected to begin in December after the government gives the green light for the construction, Mr Darun said.
As for Betong international airport, some progress has been made in constructing passenger terminal buildings at the airport, Mr Darun said.
Officials are stepping up their efforts to negotiate an agreement with landlords where the airport's runway is set to be built, he added.
Earlier, the government approved a budget of 2 billion baht to build Betong international airport in Yala.
The airport is expected to open by early 2021, he said. The airport is designed to serve smaller aircraft.
Mr Darun declined to give any details about Trang airport.