Some 4,900 passengers were stranded at Suvarnabhumi airport on Thursday due to the temporary closure of airspace over Pakistan which affected regional air traffic, especially between Asia and Europe.

Suvarnabhumi general manager Suthirawat Suwannawat said 4,000 of them were Thai Airways International travellers.

As of 1pm on Thursday, 16 inbound and 20 outbound flights were cancelled, while three flights returned on Wednesday after departing the airport, Wg Crd Suthirawat said.

THAI resumed flights to Europe on Thursday by rerouting to Chinese airspace. The airline is trying to send passengers stuck at the airport to their destinations through its allied airlines and on three planned special flights.

The flight resumption has reduced the number of THAI passengers waiting to leave the international gateway, according to Thera Buasri, director of THAI's Ground Operations Control Department.

"It's now down to 3,000 [stranded passengers]," he said. "We expect to take no longer than three days to send them all to their destinations," he said.

The terminal at Suvarnabhumi was so crowded that Immigration Bureau chief Pol Lt Gen Surachate Hakparn, tweeted a warning to "Please spare your time for your trip!''