Washington - A temporary deal to end a stalemate that has left nearly 4,000 FAA workers furloughed and brought airport construction projects to a standstill was announced by congressional leaders.

The Senate is expected to agree Friday to a House-passed version of a temporary funding extension for the agency, which expired on July 22. The extension previously was held up in the Senate because of a rider added by House Republicans that would have cut subsidies for rural airport service.

"This agreement does not resolve the important differences that still remain," Senate Majority Leader Harry Reid, D-Nev., said in a statement. "But I believe we should keep Americans working while Congress settles its differences."

The agency had been forced to put "nonessential" employees on an abrupt, unpaid leave, and required some "essential" employees to work without pay. Without the authority to collect ticket taxes from airlines, the agency also has missed out on $350 million in revenue.

While employees could be back to work as early as Monday, it's unclear for how long.

"This issue is still unresolved, as far as I'm concerned," said Dan Stefko, an engineer with the FAA who has been out of work for nearly two weeks. "It could be one and a half months before we could be right back in the same exact spot."

The Senate, which adjourned Tuesday, will vote on the House-passed bill with just a few members present under a procedure requiring the members' unanimous consent. The bill extends FAA funding through Sept.16. After the president signs it, Transportation Secretary Ray LaHood is expected to issue waivers to the 13 airports affected by the subsidy cuts in the House-passed bill.

"This is a tremendous victory for American workers everywhere," LaHood said in a statement. "From construction workers to our FAA employees, they will have the security of knowing they are going to go back to work and get a paycheck."

Lawmakers have worked for more than four years on a number of disagreements in a long-term aviation bill. Since then, 20 temporary extensions have been passed to buy them more time.

A central sticking point in the larger bill is a Republican-backed provision that would make it harder for airline and rail workers to unionize. A rule change made by the National Mediation Board last year allowed those employees to unionize with a simple majority of those voting. Republicans want to overturn that change.

Usually, extending funding for the FAA is a routine matter. This time, Republicans in the House added the airport subsidies provision, which targeted airports in states of key Democrats, as a way to exert pressure on Senate Democrats to make concessions on key provisions of the larger bill.

As late as Wednesday afternoon, congressional leaders were digging in their heels and it seemed likely the stalemate would stretch through Labor Day. Democratic lawmakers accused Republicans of "hostage taking," calling on House members to pass a "clean" extension.

President Barack Obama reached out to House Speaker John Boehner, R-Ohio, to resolve the issue Wednesday. But the speaker told the president the House had "done its work - it's up to the Senate to act," according to one GOP aide.

"House Republicans made it clear they would continue to hold the entire aviations system hostage," said Senate Transportation Chairman Jay Rockefeller, D-W.Va. "I deplore those tactics, but ultimately the stakes for real people are too high."

House Republicans were curiously silent Thursday. A statement released by Boehner's office simply said, "We are pleased the Senate has agreed to pass the House-approved FAA extension tomorrow."

After the bill goes to the president's desk employees could report to work the next business day.

But Stefko and his colleagues remain wary. "All it takes is one objection to kill a unanimous consent vote," he said. "Until that is passed, there will be no champagne being popped."