Prime Minister Prayut Chan-o-cha will visit U-Tapao airport in Rayong Wednesday, where a second terminal development is preparing to open as part of government plans to turn the facility into a third key choice for airlines.
The prime minister will inspect facilities and also meet key people from the public and private sector, a spokesman said.
Gen Prayut will inspect work on the new second terminal, which will lift airport capacity from 800,000 to 3 million people a year, and opens later this year.
In April, airport director Rear Adm Worapol Tongpricha said the 620-million-baht terminal is the heart of a three-year first-phase development, which started last year.
Together with the first terminal, it will increase annual passenger handling capacity and pave the way for further upgrades. In the second phase, the government will boost the capacity further to 5 million people, the source said.
The Prayut government sees the need to develop U-Tapao airport after a stronger aviation industry, fuelled by growth in budget airlines, puts pressure on capacity at Don Mueang and Suvarnabhumi airports.
The transport and defence ministries are working together to improve facilities at U-Tapao airport.
They want it to be a third option for airlines trying to avoid overcrowded Don Mueang and Suvarnabhumi airports as well as serving as an "emergency airport" in the event the other two airports face problems.
Located in Rayong's Ban Chang district, U-Tapao serves five airlines -- Air Asia, Bangkok Airways, Kan Airlines, R Airlines and China Southern Airlines.
In the long term, the source added, an Airport Rail Link extension will be built, linking Don Mueang, Suvarnabhumi and U-Tapao airports together. This could also feed into tourism, as the seaside resort of Pattaya is nearby.
At present, the Airport Rail Link connects Suvarnabhumi and a BTS station in Phaya Thai in central Bangkok on a 28.6-km line.