Passengers taking taxicabs from National Airport will pay 50 cents more for each ride starting Sunday that will help pay for a new taxi holding area designed to relieve traffic congestion on the airport road.

The prospect of higher fares had cabdrivers grumbling yesterday, but passengers mostly shrugged at the news.

"I guess the realities are that everything is going up," said Sherry Embrey of Alexandria, who was waiting in one of the airport's taxicab lines after returning from a business trip. "It's a service and you've got to pay for it."

But Sawarn S. Dhillon, like other drivers waiting to pick up passengers, said the increase will be "bad for taxi drivers." He said Washington passengers already are small tippers, and if they have to pay more in fares, then "maybe no tip."

More than one in five passengers who arrive at National leave in taxis, according to Metropolitan Washington Airports Authority records. Officials said 1.7 million taxis were dispatched from National last year.

Taxicabs now pay 50 cents to pick up passengers at National, and the fee is added to the passenger's fare. It helps pay for the dispatchers who stand at the curb and direct passengers to their cabs.

The fee was set in 1974. But since 1986, the revenue has not covered the costs of the dispatching service, forcing the authority to cover the difference with a subsidy that reached $171,000 last year.

When the fee doubles to $1 on Sunday, the increase in revenue should eliminate the need for a subsidy and also will be used to help pay for the new taxicab holding area.

The $5.2 million, two-level structure is expected to open in August and hold about 500 cabs, clearing much of the usually congested roadway leading to the terminals for other motorists. The garage is one part of the authority's $735 million improvement plan for the airport.

"If it would help the traffic, then I'm all for it," said Stephen Hopkins of Northwest Washington, as he waited for a cab. "There are serious traffic problems here and I'd like to see that solved."

But some passengers said they don't like the idea of paying more. "I disapprove. What is the advantage to the passenger? Do I get better service or just pay more?" said Thomas Simon of Portsmouth, England.

Some taxi drivers have expressed support for construction of the new garage, but all those interviewed worried that the increase would hurt business.

National is heavily used by business travelers, and those interviewed generally said they didn't mind the increase because it will be covered by their expense accounts.

"I don't really care," said Stephen Kravitsky of Grand Forks, N.D., as he waited in the taxi line. "I'm here on business and it's still the quickest means to get to my hotel."