A group representing the airlines at National Airport, worried that fixing a design flaw in the new terminal there could lead to higher costs and angry travelers, is urging the airport authority to reject costly proposals to relocate the terminal, and instead to build a new control tower.

One plan that would raise the terminal's cost by $100 million also would result in higher rental rates and landing fees charged to airlines, which the airlines say they would pass on to travelers. Even though the terminal's cost will be paid off over several decades, airline officials say travelers would immediately notice higher ticket prices.

"We think the answer is a new tower," said Dick DeiTos, executive director of the Metropolitan Washington Airlines Committee, which represents the airlines before the authority. He noted that Chicago's O'Hare International Airport recently built a new control tower for $15 million.

Airport officials are considering several solutions to the design problem that allows one of the new terminal's three arms to block the existing control tower's view of a runway. Last week, several members of the authority's board expressed interest in moving the terminal site west, adjacent to the Metro station.

That would solve the problem, but could cost up to $100 million more than any solution that does not involve relocating the terminal.

Airport officials are reluctant to increase the height of National's existing tower, which sits atop the airport's 49-year-old main terminal. The main terminal and tower are scheduled to be preserved under National's $735 million renovation program.

Several officials of individual airlines say privately that they favor leaving the existing tower in place and building a new tower in another location, perhaps on top of one of three parking garages scheduled to be constructed near the new terminal.

Many airline officials also do not want the terminal built adjacent to the Metro station because it would require relocating a two-level road that would serve the terminal.

Original plans called for the road to be located between the Metro station and the terminal. The road would be relocated west of the station if the terminal is moved.

About 80 percent of those who now use National arrive by car, and airlines are reluctant to increase the distance that most of their customers must walk.

Dave Shipley, spokesman for USAir, said the company has not stated an opinion on National's new terminal. "The whole matter is under review," he said.

Other airlines operating at National, including American, TWA, Eastern and America West, would not comment publicly.

Steve Hayes, spokesman for the Air Transport Association, which also represents the airline industry, said the possible increase in the new terminal's price tag is daunting to many airlines, particularly at a time when some are facing a market with fewer passengers and rising operating costs.

"Clearly to date this has not been a good year for the airlines," said Hayes, noting that fuel costs have jumped because of the Middle East conflict. "Airlines are looking to cut costs any way they can."

Board member Carrington Williams, chairman of the authority's planning committee, said that although he still is considering plans to build a new tower, "I'm not swept away by what the airlines say."

"We're looking at building this terminal from a 50-year perspective," Williams said. "They are usually more interested in what's happening next quarter, or what Wall Street is saying about them."

The board's rush to solve the design problem began about two months ago when several board members first learned of the problem, which the authority's staff members had known about for two years. Board members and the authority's staff, who thought the problem was relatively minor, say poor communications kept some board members in the dark.

James A. Wilding, the authority's general manager, said that until recently, he thought board members had known about the design flaw for some time. Wilding said that when Williams and other board members expressed surprise when they learned about it, "My reaction was, 'I'm surprised you're surprised.' "

Wilding and the authority's staff have long believed that the design problem could be solved relatively inexpensively by shortening or repositioning the northern arm of the planned terminal. As originally planned, the arm would block the control tower's view of Runway 15-33, a 5,189-foot strip used primarily by commuter and private aircraft.

Such a solution is among those being considered by the board, although several board members say the low ceiling heights that would be required in the plan would harm the terminal's appearance.