Among the protesters at Bangkok's Suvarnabhumi airport
Protesters occupying Bangkok's main airports have allowed dozens of empty planes to fly to provincial airports to pick up stranded tourists.
At least 100,000 foreign visitors have been unable to leave the country since the anti-government activists occupied the international airport last week.
Meanwhile, protesters are vacating a central government complex after an occupation of more than three months.
The protest has struck a large blow to Thailand's economy, say correspondents.
Tourism is a major source of revenue for the country, and the crisis will also have knock-on effects for Thailand's neighbours, because Bangkok is a major international hub, they say.
Thailand's deputy premier for economic affairs is reported to be meeting senior figures in commerce, industry and tourism on Monday to discuss the damage being done by the protest siege.
Thousands of travellers have been stranded since the anti-government People's Alliance for Democracy (PAD) took over Bangkok's international and domestic airports last week.
Authorities have reached a deal to allow a total of 88 planes to be flown out to other Thai airports, where it is hoped they can evacuate some of the blockaded tourists.
The PAD seems to be focusing its resources on the airport occupations
Meanwhile, hundreds of protesters are vacating Government House in central Bangkok, more than three months after they occupied it to demand the resignation of the government and the reform of Thailand's political system.
They say it is now too dangerous to continue the occupation, after explosions on Sunday - including the use of hand grenades - injured at least 49 people there.
Thousands of pro-government protesters also besieged Bangkok on Sunday in a counter-demonstration.
But PAD leaders have directed the followers vacating the complex to bolster the airport occupations, and correspondents caution that these developments do not signal the fatal weakening of the protesters' disruptive campaign.
Analysts say the occupation is, if anything, becoming more entrenched.
The feeling is spreading in Thailand that the end-game is approaching: that protesters, possibly backed by sections of the army and the royalist elite, appear determined to force the government out by paralysing the country, he says.
Earlier on Monday, a spokeswoman for Airports of Thailand said: "Thirty-seven aircraft have left Suvarnabhumi [international airport] since the first aircraft of Siam GA [a regional airline] took off on Sunday evening.
"International airlines will have to contact us to take those stranded aircraft out of Suvarnabhumi."
Twelve planes belonging to foreign airlines are stranded at Suvarnabhumi, as well as 29 from Thai Airways, 16 of Thai Airasia, 15 from Bangkok Airways, and 22 aircraft from other airlines.
With thousands of British citizens among the estimated 100,000 travellers, a spokesman for the UK's Foreign Office said: "Bangkok's two main airports remain closed but airlines have been able to arrange flights and transfers to and from alternative airports.
"Some British nationals have been able to fly out but not in the necessary numbers.
"We have continued our consultations with airlines and Thai authorities... and action is being stepped up to enable people to travel in greater numbers, for example via Chiang Mai."
Chiang Mai, in the north, is 700km (435 miles) by road from Bangkok, while another option - Phuket, a resort in the south - is 850km.
France and reportedly Spain have also chartered planes to pick up nationals at the Vietnam war-era U-Tapao naval base south-east of Bangkok, though France has warned that it will only be able to evacuate the most urgent cases.
Air France-KLM and Australia's Qantas have also sent extra planes to Phuket.
On Sunday more than 450 Muslim pilgrims stranded at the international airport were taken by bus to the base where they were to board a plane for the annual Hajj in Saudi Arabia.
Thailand's tourist industry is losing an estimated $85m (£55.4m) per day, and the government warns that the number of foreign tourists arriving next year may halve, threatening one million jobs.
Among the PAD protesters are royalists, businessmen and the urban middle class.
The opposition want the government to resign, accusing it of being corrupt, hostile to the monarchy and in league with exiled former Prime Minister Thaksin Shinawatra.
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