WASHINGTON (Reuters) - Congressional leaders reached a breakthrough compromise on Friday on the most difficult issue holding up action on long-stalled U.S. aviation legislation that would accelerate modernization of the aging air traffic system.
Leaders in the Senate and House of Representatives agreed to modify politically charged language on how airline unions conduct their elections, partly meeting Republican demands to reform U.S. oversight of representation balloting, congressional aides said.
Other issues remain on the table, but sources with knowledge of the negotiations have said they could be resolved once the labor provision, which could most benefit Delta Air Lines initially, was settled.
Inaction since 2007 on the legislation laying out Federal Aviation Administration (FAA) policies and spending plans has required that Congress approve a string of temporary measures to keep the agency overseeing air traffic services fully funded.
The current extension expires on January 31, but it is unclear whether negotiators will resolve remaining differences in time to approve the overarching bill or whether another stop-gap spending extension will be required.
Sharp political wrangling over the labor issue and another involving subsides for rural airline service triggered a two-week shutdown of airport construction programs last summer.
(Reporting By John Crawley; Editing by Philip Barbara)