Alarm in the aviation industry over a projected 10 percent drop in domestic flights this winter didn't derail plans to open multimillion-dollar runways at three U.S. airports Thursday.

Despite global economic woes that have fewer people taking to the skies, airport officials are heralding the new capacity as crucial to alleviating congestion and delays, especially in the long term.

They say that's worth the more than $450 million spent on the runway at Chicago's O'Hare International; the approximately $350 million spent at Dulles International, just outside Washington, D.C.; and the more than $1 billion for Seattle-Tacoma International.

"This is absolutely critical, absolutely necessary, absolutely money well spent," said Rosemarie Andolino, who leads the ongoing $15 billion expansion of O'Hare, a vital global hub that inaugurated its first new runway in nearly 40 years.

Dulles' first new runway since the airport's 1962 opening got up and running Thursday morning when an American Airlines flight bound for Los Angeles took off, kicking up a small cloud of construction dust.

U.S. Transportation Secretary Mary Peters, who planned to visit all three opening ceremonies Thursday, likened Dulles' runway to an early gift for holiday travelers. But air traffic controllers note taxiways needed to make the new runway fully functional won't be complete until summer.

Others call the construction work a positive step but note more needs to be done.

"The greater challenge will be to do something about modernizing air space so that those improvements in efficiency on the ground is matched in the air," said David Castelveter, a spokesman for the Air Transport Association, which represents U.S. carriers.

The association backs a Federal Aviation Administration push for a new satellite-based network that would let planes fly using GPS instead of radar. Funding and implementation issues have hampered the $30 billion project.

Meanwhile, nationwide bottlenecks, particularly around chronically clogged New York City-area airports, will continue hampering delay-reduction efforts, Castelveter predicted.

The FAA acknowledges that new runways aren't the sole answer to solving delays, noting in a 2007 report that just two major U.S. airports have opened in the past 40 years — Dallas-Fort Worth and Denver International — and that as many as four need to be built in the next two to three decades.

Despite current downturns — data show domestic flights fell 6 percent in August — air travel is still expected to rise from the approximately 700 million air travelers in 2007 to more than 1 billion annually during the next decade.

Detractors have criticized the Seattle-Tacoma runway's billion-dollar price tag, which is five times initial estimates. Defenders say it will more than pay for itself in decades to come, including by reducing delays.

In Chicago, Andolino concedes that O'Hare delays won't be dramatically reduced until completion of the airport's entire multibillion-dollar expansion, which envisions another new runway and terminal by 2014. But O'Hare hasn't secured funding for that second phase and six of the airport's carriers are balking at the cost in light of economic woes.