Many drivers who dropped off travelers at Dulles International Airport on Thursday evening found that it took longer to get out of the main parking lot than to drive the 27 miles from there to the District of Columbia.

It's an incredible turn of events for an airport that, until quite recently, had a reputation as a nearly deserted white elephant.

And if one thought Thursday was bad, last night was predictably worse, according to airport manager Dexter Davis, as the real exodus of holiday travelers got under way. Nationally, according to the American Automobile Association, about 42 million Americans -- 18 percent of the population -- are expected to make intercity trips during the holiday period. Of those, 90 percent will drive.

One driver leaving Dulles on Thursday got into his car in the so-called hourly parking lot in front of the main terminal precisely as the 6 p.m. news came on the radio. It was 6:34 p.m. before the line inched to the cashier's booth, with the charge voluntarily reduced to reflect the waiting time.

At 7:05, the car approached Rosslyn and the bridge into Washington. That means the driving took 31 minutes, the waiting 34.

Airport manager Davis said parking, especially in the 3,800-space lot in front of the terminal, is "probably the worst customer service aspect of the airport right now . . . . It's not acceptable . . . . In January, we will have 300 more spaces when the rental cars are moved out" and a shuttle system is instituted, he said. The location of the cashier's booth prevents opening more lanes, he added.