Four thousand furloughed Federal Aviation Administration employees will probably not return to work until September at the earliest because the House began its August recess Monday night before resolving an impasse over the bill that authorizes the agency.

Senate Commerce Chairman Jay Rockefeller (D-W.Va.) on Monday evening made a last-minute attempt to pass an extension of the FAA authorization law through mid-September, but the proposal was blocked by Senate Finance ranking member Orrin Hatch (R-Utah).

Even if the Senate had passed the extension, House GOP leadership aides had said there were no plans to take up a Senate-passed FAA extension before adjourning.

The FAA partially shut down July 23 after the impasse.

Rockefeller was critical of a short-term extension passed July 20 by the House, which would have cut about $16 million from the Essential Air Service program, which provides subsidized air service to rural communities. Senate Democrats also oppose a provision in a multi-year extension from the House that would make it harder for airline and railroad workers to unionize.

“The House-passed extension is not good policy; its about politics,” Rockefeller said.

Hatch said that he wants a full authorization.

“My concern is that the White House … will continue to hide behind a series of short-term extensions,” said Hatch, who is up for re-election in 2012. He added that unions have held up the measure.

“Favors to organized labor have overshadowed the prospects of a long-term FAA bill,” Hatch said.

At issue is a provision in the longer-term House bill to overturn a National Mediation Board ruling that says nonvoting employees should not be counted in the union election.

Before the rule, which was changed last year, airline and railroad employees who did not vote on whether to unionize were considered to have voted against organizing a union.

Hatch said the rule overturns 75 years of labor law.

Earlier Monday, Transportation Secretary Ray LaHood said he had been pressing Congress for a compromise.

“I am urging Congress to take steps to take action, to pass legislation so that people can go back to work and negotiations can begin on whatever the sticking points are that Members of Congress feel they need in a final FAA bill,” LaHood said on a conference call with reporters.

LaHood, who wanted a two-month extension, said he had spoken Monday with Senate Majority Leader Harry Reid (D-Nev.) and Senate Majority Whip Dick Durbin (D-Ill.).

He also said he had several phone conversations with the staff of Speaker John Boehner (R-Ohio) during the weekend, as well as with members of the House Transportation and Infrastructure Committee.

“I have been on the phone all weekend with people that can make this happen,” LaHood said. “I want to see our people go back to work, I want to see these construction projects start and I want to see 70,000 construction workers also go back to work.”

Rep. Peter DeFazio (D-Ore.), a veteran member of the House Transportation committee, said he was disappointed the issue was not settled in the debt limit deal.

“Minimally, they could have restored funding and taxation that funds the Federal Aviation Administration,” DeFazio said. “That would put 94,000 people back to work. They didn’t even do that. There’s no investment, no jobs, coming out of this bill.”

“They didn’t want anything extraneous in this package,” a visibly upset DeFazio said. “Extraneous? Jobs are extraneous? Safety and security is extraneous? $200 million a week in lost revenue is extraneous? What’s the package about? It’s all about cutting, cutting, cutting.”

About 40 FAA safety inspectors continue to work without pay.

“They are traveling around the country at their own expense,” said FAA Deputy Director Michael Huerta, who added that they cannot be reimbursed until Congress acts.

Air traffic controllers also remain on the job.

Correction: Aug. 3, 2011

The article misstated what legislation contained language that would make it more difficult for airline and rail workers to unionize. That provision was contained in a multiyear Federal Aviation Administration reauthorization that the House passed.

Jessica Brady contributed to this story.