The airport is the last to reopen after the Sept. 11 terrorist attacks. Authorities had been concerned because the airport's normal flight paths followed the Potomac River, bringing planes close to CIA headquarters, the White House, the Capitol and the Pentagon.
From now on flights from the north will follow a straight line to the airport over some residential areas.
The airport will offer shuttle flights to New York and Boston and limited service to other cities, according to the Metropolitan Washington Airports Authority.
Travelers will face a gantlet of precautions before they can get close to a plane.
All passengers will have to go through two security checkpoints, show identification twice and be limited to one carryon bag. They will also be subject to random screenings with handheld metal detectors. Airlines are advising passengers to arrive two hours before their flights and to expect long lines.
There also will be expanded identification checks for airport employees and flight crews, and more police and K-9 patrols.
On Wednesday, work crews installed several new X-ray machines at the check-in counters. Brought in on forklifts, the 7,000-pound machines use computers to compare a bag's contents with a database of explosives and weapons.
Sharon Hamilton, 36, who manages three newsstands at the airport, restocked magazine racks that had been unchanged since Sept. 11.
"We're making it fresh," she said. "I'll be glad to get back to work, but it's going to be a headache with the security."
Members of Congress from the region had pushed for reopening the airport, which is located on the Virginia side of the Potomac and is much closer to Capitol Hill than Dulles Airport.
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