A conservative watchdog group has filed a lawsuit against the Pentagon seeking travel details for the Obama administration officials and U.S. lawmakers who flew to Copenhagen, Denmark, for the United Nations Climate Change Conference in December 2009.

Judicial Watch filed the lawsuit on behalf of Pajamas Media (PJM), a conservative outlet that first requested the records from the Air Force under the Freedom of Information Act around the time of the conference.

Six months later, the Air Force responded, telling Pajamas Media that part of the request had been forwarded to the office of the secretary. Then in May this year, the office of secretary released four pages of mostly redacted material and told Pajamas Media that it referred the withheld material to the U.S. Secret Service.

Judicial Watch says the Air Force has failed to turn over any records responsive to PJM's FOIA request or show that the withheld material is legally exempt from public release. The Air Force also has not indicated whether or when it will release the requested records.

"What happened to the transparency that candidate Obama promised," Pajamas Media CEO Roger L. Simon said in a statement. "It has taken almost a year for this administration to turn over a flight manifest, and then that document was heavily redacted. The Obama administration has proven itself to be one of the most secretive administrations in history."

The Air Force declined to comment.

Judicial Watch is asking the court to order the Air Force to conduct a search for "any and all responsive records," to set a specific date that Pajamas Media is to receive the requested documents and to provide the company with an index describing the records that are being withheld under claims of exemption.

Roughly 16,500 delegates, activists and reporters gathered at Copenhagen for the 12-day conference, which the U.N. estimated created 40,584 tons of carbon dioxide equivalents, roughly the same amount as the carbon emissions of Morocco in 2006.

Obama traveled to the Danish capital with a U.S. delegation of more than 165, including at least 106 lawmakers from both political parties. The congressional delegation cost taxpayers more than $1 million, including $4,406 to provide food and rooms for two nights for 15 Democratic and half a dozen Republican lawmakers, according to a CBS News investigation of congressional expense reports. But it's still not clear how much taxpayer money Obama's 60-person entourage cost.

The Denmark conference fell way short of expectations, producing nothing more than a nonbinding "Copenhagen Accord," under which at least 85 nations said they will take action to rein in emissions. But researchers said those pledges, including the Obama administration's goal of reducing U.S. emissions by 17 percent below 2005 levels by 2020, didn't rise to what's needed to keep the atmosphere from warming dangerously though this century.

"The December 2009 United Nations 'climate change' conference in Copenhagen must have been embarrassing for global warming activists and their associates in Washington," Judicial Watch President Tom Fitton said in a written statement. "The conference not only failed to enact worldwide 'climate' action, but the airlift of President Obama and other government officials must have resulted in huge, wasteful costs for the American people. No wonder PJM can't get anything out of the administration about that disastrous conference."