Somchai and another 59 members of the ruling coalition leaders were banned from politics for five years.
On Wednesday however PPP members said they planned to regroup under a new name, the "For Thais Party", and meet as early as Monday to select a new prime minister.
That could possibly set the stage for further confrontation.
|The PAD celebrated victory after Tuesday's court ruling against the prime minister [AFP]
Following Tuesday's court verdict, activists from the People's Alliance for Democracy (PAD), which has led the protests against Somchai's government, were seen joining efforts to clean up the airport terminal and return it to business as usual.
"It's sad to say goodbye, but our job here is done, so we must go home," said
Saisuri Pantupradij, a 45-year-old PAD supporter who had been camped out at the airport.
"We want to clean up the airport before we leave. We want PAD to have a good image," said Bow Piyapat, another protesters, as she wielded a mop around rows of check-in counters.
The PAD occupied Suvarnabhumi and Don Muang last week, stranding 350,000 passengers and causing losses estimated in the hundreds of millions of dollars for the Thai economy.
On Tuesday, thousands of jubilant anti-government demonstrators danced and sang in the main hall of the airport, declaring victory after the court also ordered the dissolution of the three parties making up the ruling coalition.
While the airport siege appears to be easing, the Association of Southeast Asian Nations (Asean), has postponed a summit due to be held in Thailand.
The meeting of the regional grouping had been scheduled for December 15-18 in the northern city of Chiang Mai. It had already been moved out of Bangkok because of the political turmoil that has engulfed the capital for several weeks.
"The Cabinet agreed to cancel the Asean meeting until March because of the political turbulence in Thailand,'' Nattawut Sai-Kua, a government spokesman, told AFP news agency.
As the current chair of Asean, Thailand was due to host the group's annual summit.
Commenting on Tuesday's court ruling, Surin Pitsuwan, the Asean secretary-general and a former Thai foreign minister, said that the dismissal of Somchai had "at least put a stop to the slide into chaos".
But he warned the situation in the country remained "quite fragile [and] it will take some time to find a balance".
'Setting an example'
|Pro-government supporters have vowed to regroup and elect a new leader [EPA]
Chat Chalavorn, the head of the constitutional court's nine-judge panel, said they had decided to dissolve Somchai's People Power party (PPP), the Chart Thai party and the Machima Thipatai party "to set a political standard and an example".
The Thai Rak Thai party, which was similarly dissolved by a military-appointed constitutional tribunal in May last year, regrouped as the PPP soon after.
Parnthep Pourpangan, a spokesman for the PAD told Al Jazeera that the verdict by the constitutional court was a victory for the people.
"We have been trying to protect the constitution, and the PPP have been trying to amend it to put forward their interests," he said.
But Sunai Phasuk of Human Rights Watch, told Al Jazeera that the PAD had "successfully manipulated Thailand's democratic process".
"The main reason they have managed to get away with it is by brainwashing people," he said.
"They tell everyone they are acting in the name of protecting the constitution, and upholding democracy ... but all they have done is put the independence of the judiciary into question."
The yellow-shirted PAD supporters have been trying for months to force Somchai out, accusing him of being a proxy for Thaksin Shinawatra, the premier ousted in a 2006 coup and the original target of the anti-government campaign.
They also warned that they would return to the streets if political change does not occur.
"The PAD will return if another [Thaksin] proxy government is formed or anyone tries to amend the constitution or the law to whitewash some politicians or to subdue the monarch's royal authority," Sondhi Limthongkul, one of the protest leaders, warned on Tuesday night.