However, the terminal will raise the airport's annual passenger-handling capacity to 30 million when the building opens for commercial operation, which would be better in the long run, he added.
Don Mueang International Airport, which serves as the country's hub for budget airlines, has grown rapidly in passenger numbers over the years, Mr Prasong said.
Figures show that from January to September this year, about 26 million passengers passed through the airport even though it was designed for a maximum of 18.5 million passenger per year, he said.
Woraneti Lahprabang, managing director of THAI Smile Airways, said the delays at Terminal 2 would not affect his airline's operation but it would cause heavy congestion at the airport, which was a concern...
"We believe AoT will be able to handle the airport congestion problem during the high season as it has in the past," he said.
Mr Woraneti said the proliferation of terminals would raise the AoT's potential to handle increasing numbers of passengers in the future.
Mr Woraneti said THAI Smile has rescheduled winter flights to deal with the increasing passenger numbers, he said.
As part of its plan, the airline would switch from using Don Mueang International Airport to Suvarnabhumi airport during peak season, he added.
Meanwhile, Pramook Chaiyawan, executive chairman of New Gen Airways, a chartered carrier, said the delays would not cause any damage to his company's business.
The company could manage operation times for chartered flights to avoid airport congestion, he added.
Mr Pramook said he was worried about whether the airport's number of aircraft apron areas will be adequate, as he feared that when Terminal 2 at Don Mueang International Airport officially opens for service,...
Mr Pramook said he will ask the AoT to look into the problem.