An airplane docks at Suvarnabhumi airport in Samut Prakan province on Feb 17. (Photo: Somchai Poomlard)

Flight cancellations could result in a 15-20% year-on-year decrease in overall outbound trips during the low season, and a 10% decline for the full year.

Thai airlines have reduced capacity on certain routes, such as Thai AirAsia X's Bangkok–Sapporo route and Thai AirAsia's China routes during the remaining summer schedule, while Thai Airways has also cut several domestic and international routes in May.

Chotechuang Soorangura, vice-president of the Thai Travel Agents Association (TTAA), said airlines are reducing or merging flights that are unprofitable or less popular in order to adjust to current demand and rising fuel prices.

So far, tour groups have not been impacted by these changes, as this period is not a peak season for Thai tourists.

Even though tour companies have already sold tour packages and their flights are cancelled, they can still obtain refunds from airlines and offer alternative flights with other foreign carriers, which are still operating from major cities on similar schedules.

"Travelling abroad is now limited to certain groups. Only some companies and premium leisure segments can still afford to take trips," he said.

Mr Chotechuang said Thais are concerned about living costs and are restricting their spending. Government and public organisations have also cancelled overseas trips, following a policy of budget and energy conservation.

In previous Songkran periods, some travel agents asked customers to pay additional charges to cover higher airfares due to fuel surcharges. This applied only to cases where travel agents had reserved tickets but not yet made full payment.

Rising airfares in the coming months are also pushing tour package prices up by 20%. During the summer schedule, which coincides with the low season, outbound travel could fall by 15-20% compared with last year, he said.

Mr Chotechuang, who is also managing director of NS Travel and Tours, said his company is adjusting its strategy by selling more domestic tour packages, such as to corporate travellers shifting from overseas trips.

There is pent-up demand from Thai tourists waiting to travel next winter, especially to Europe and other long-haul destinations, after delaying their plans during the Songkran holiday, once international flights return to normal and fuel prices stabilise.

Therefore, outbound travel this year could fall by up to 10% year-on-year, he said. Top destinations this year remain China and Japan.