The outlook isn't bright for a quick deal on a new, multiyear aviation bill, because the Senate and House haven't bridged a wide gap on funding levels for airport construction grants. They also have been unable to resolve a disagreement on a labor issue.

Negotiators, led by Senate commerce committee Chairman Jay Rockefeller (D-W.Va.) and House Transportation and Infrastructure Committee Chairman John Mica (R-Fla.), have been working to settle differences between the long-term Federal Aviation Administration authorizations the two chambers passed this year.

But with no agreement yet in sight, lawmakers cleared another short-term extension to keep Airport Improvement Program (AIP) construction grants flowing and other FAA activities operating. The new stopgap, enacted on May 31, runs through June 30. It is the 19th FAA extension since Sept. 30, 2007, when the last long-term bill lapsed.

Todd Hauptli, American Association of Airport Executives senior executive vice president, says, “I am optimistic that they will get a bill done before the end of the [calendar] year. I am not as optimistic that they will get it done before the end of the month. I think there's a pretty good chance they'll need yet another extension.”

The Senate passed a two-year FAA measure in February, and the House approved a four-year bill in April. But there are major differences between the two that have yet to be worked out.

One big issue is money. Previous Senate and House bills agreed on funding levels for AIP. But that changed this year after Republicans took control of the House and approved a bill that would cut AIP sharply, to an average of about $3 billion a year. The Senate version, by comparison, averages about $4 billion annually. AIP's 2011 obligation limit is slightly more than $3.5 billion.

In addition, the White House issued a veto warning over House language that would repeal a 2010 National Mediation Board rule that changes procedures for airline and railroad workers' union elections.

While Congress struggles with the legislation, airport officials have had to endure stopgap authorizations that have stretched for 44 months—and counting. Jane Calder-wood, Airports Council International-North America vice president for government and political affairs, says, “It's very hard to plan when you don't know what the funding level is.” Calderwood says some projects have been delayed and some airports have gone forward with only portions of projects, based on funding available. “Sometimes that ends up actually costing you more when you have to do it piecemeal,” she notes.