Justin Harclerode, a spokesperson for House Transportation and Infrastructure Committee Chairman John Mica (R-Fla.), said, "We can now move ahead on this critical long-term infrastructure measure to create jobs, modernize our air traffic control system and reduce the size of government."

The House had passed a four-year FAA bill in February 2011 and the Senate approved a two-year measure in April. The two bills differed on a range of issues, including funding for FAA Airport Improvement Program infrastructure grants. The House measure would provide about $3 billion a year for the grant program; the Senate version averages $4 billion annually.

But the biggest obstacle blocking a multi-year FAA bill agreement was House language that would undo a 2010 National Mediation Board (NMB) rule governing unionization elections for airline and railroad workers. Senate Democrats wanted to keep the 2010 regulation, which is seen as favoring organized labor.

The Reid-Boehner agreement includes changes in NMB election procedures. According to a congressional source, the agreement raises the threshold needed to call an unionizing election to 50% of those eligible to vote, from 35% under the current NMB rule in an election to adopt a new union. The level required to change or decertify an existing union would remain at 50%.

In addition, run-off elections overseen by the NMB will include a no-union choice, if that option was one of the top two vote-getters in the initial workplace election. At present, a run-off pits the top two vote-getting unions from the first election.

The deal also calls for public hearings for all significant NMB rulemakings and a Government Accountability Office report on union certification procedures that compares NMB procedures with those used by other federal and state labor-related agencies. 

There was no announcement on how much funding would be in the final bill.

Updated Jan. 24, to include House vote on extension.