The Bangkok Post had the initial report:

The anti-government United Front for Democracy against Dictatorship is planning to stage a rally on the main road leading to Suvarnabhumi airport next week.

One of the group’s core leaders, Natthawut Saikua, yesterday said the rally was intended to press for progress in the prosecution of the UDD’s political rivals, the People’s Alliance for Democracy, for its extended blockade of the airport in late 2008.

Mr Natthawut said the protest would be peaceful. The group would not lay siege to the terminal and they would not block off the airport’s entrances.

Other protest groups, such as farmers troubled by the government’s policies and laid-off workers, had been asked to join the rally.

Ambika of Reuters:

Thai “red shirt” demonstrators are planning a symbolic rally next week near Bangkok’s main airport, but insisted on Wednesday there would be no repeat of a crippling blockade a year ago by a rival protest movement.

The anti-government group said it was considering a brief demonstration on the road leading to Suvarnabhumi Airport to highlight the government’s failure to prosecute “yellow shirt” protestors who shut down two airports in December 2008.
…
“If we go to the airport, it will be a symbolic rally. We won’t bring many people,” said Arisman Pongruangrong, a folk singer and key activist with the United Front for Democracy Against Dictatorship (UDD), the “red shirts” formal name.

“We won’t close the airport or shut down traffic. We just want to tell the world that the government is unfair and practices double standards,” he added.

Of course, then we had the apocalyptic shock from some in the Bangkok Post:

Satit Rungkasiri, the director-general of the Finance Ministry’s Fiscal Policy Office, warned that an airport closure would be akin to “national suicide”.

“If the airport is closed due to political protests, it would be a problem for the economy on par with the Map Ta Phut dispute. No one, no country, could accept a second closure for its main airport,” he said.

Serirat Prasutanond, the president of Airports of Thailand, offered a public plea for the red-shirts to drop the protest.

“Any [protest] will be certainly negative for our tourism industry and our country’s image. We paid dearly for the airport closure in 2008. Please don’t let this happen again,” he said.

Thai Hotels Association president Prakit Chinamourphong said Thailand’s global image would be “destroyed” if the airport was closed.

“The government must do everything, even if it means drastic measures, to protect the airport,” he said.

BP: A short, symbolic protest near the airport produces this reaction. In the end, the red shirts called off the rally, but as Bangkok Dan noted the government panic was clear to see. Not really sure what to make of all of this.