With a slight thump as the towing rope lets go, Glenn Collins's glider gently banked right, corkscrewing upward into the cloudless, hazy sky over Frederick County.

It's a rush, rising on invisible currents of air, one that Collins relishes even more than the time he spent in the back seat of an F-15E Strike Eagle during the Persian Gulf War.

The search for that feeling draws Collins and the rest of the Mid-Atlantic Soaring Association to Frederick Municipal Airport each weekend, when they can fly until gravity and darkness force them to land.

But the 165 members of the region's largest glider club are worried that there soon won't be a place for them to come down. In late December, Charles M. Abell, the airport manager, closed off a grassy area the club had used as a runway since 1992, saying the zone is not officially authorized for landings and takeoffs.

Powerless in the air, but not on the ground, club members said last week that they would sue the city if their runway is not reopened.

Although club members have switched to an asphalt runway that parallels the grass one, they said they fear that Abell's move is a prelude to forcing them out of the Frederick airport entirely. In the same way that a golf cart would gum up traffic on the Capital Beltway, gliders could get in the way of heavier, more profitable jet and propeller plane traffic. Powered aircraft generate more revenue for the airport because they require fuel and more maintenance.

"Their idea is to turn us into Wal-Mart, and soaring will be history," said Gerard E. Evans, the Maryland lobbyist retained by the glider group.

Abell said that he did not intend to shut down the glider club, which has operated at the airport since 1966. "I have the highest respect for those fellas in that organization," he said, noting that he had pressed for a study on the feasibility of a turf runway. "The last thing I want to do is take away flying privileges."

In the middle of this dispute is Frederick Mayor Jennifer P. Dougherty, who has final authority over the airport.

Dougherty said she is trying to work out a compromise and has no interest in ejecting the club.

"Is Charlie [Abell] trying to get rid of the gliders?" Dougherty asked. "I don't know if Charlie is. I'm not."

Members of the glider club have drawn a line in the grass, digging up airport plans, decade-old correspondence from the city government and the Federal Aviation Administration and grant proposals from the 1980s that they say justify their use of the area as a runway.

The debate comes down to this: Abell says that the grass runway does not exist, because it has not been recognized by the FAA. Officials of the FAA's Washington Airports District Office agree, saying that continued use of the grass area could cause a cutoff of federal grant money to the airport.

Club members say that they have used the area as a runway for more than a decade without serious accidents and that records, including approved maps, have referred to it as a "glider operations area" or runway.

They also say the asphalt runway they have been using is unsafe. It is narrower than the grass strip, and gliders, with their large wingspans, can knock out lights along the side. Asphalt also wears out tow ropes faster, resulting in sudden rope breaks during takeoffs. While pilots train for these mishaps, they can be dangerous.

George Simms Jr., an antiaircraft gunner in the Korean War who started flying in 1964, said he had gone his entire gliding career without a rope break until he started using the asphalt runway. "Now I've had two in one day," he said.

Simms and several other club members said they want Dougherty to intervene and order the grass area reopened in lieu of a lawsuit. But Abell and Dougherty said the city would face a legal liability if an accident occurred on the grass strip.

"The responsibility is mine to avoid either a runway collision or a midair collision or an accident," Dougherty said. "I've got two people, the manager and the FAA, saying, 'Your runway doesn't meet the specs.' And if I ignored that and reactivated the turf runway and something happened, small or large, I don't think I would be in a very good legal position or a moral position."

Dougherty seemed reluctant to take sides. "I don't know who started it, but I kind of feel like the mom that keeps the two sides from fighting," she said. "I just want to have it clear that I haven't shut the door on anything," she said later.

Abell all but said, "See you in court."

"If they feel they've been unjustly discriminated against, they certainly have that right," he said. "That's a good American way."

In the end, though, the issue would not matter if club members weren't worried that Abell means to do away with gliding entirely.

With the sport of soaring in slow decline across the country, the club is one of the few to have steady membership in recent decades.

The club also has several teenage trainees -- Frederick is one of the few places where the region's gliding fans can go to pursue their passion.

Last weekend, a few dozen pilots drove in under a blazing sun that heated the asphalt to baking temperature.

"It's an addiction," said Dave Schober, a glider pilot.

With that, he climbed into his Piper Pawnee tow plane to pull Collins off the runway into the sky. The glider lifted off the runway before Schober's plane, then did a delicate dance as Collins tried to hold position behind the powered plane.

As the glider crossed 2,500 feet, Collins pulled a knob to release the tow rope.

The Grob Twin Astir, the Cadillac of two-seaters, snapped free, surfing upward on a rising column of warm air.

A patchwork of farms, interstates, quarries and a golf course spread out below, and a couple of turkey vultures lazily circled the airport, looking for something to eat. But for the air rushing into the cockpit through a small vent, it was silent.

A glider is towed into the air at Frederick Municipal Airport. A glider club is using an asphalt runway but wants a grassy area nearby reopened for takeoffs and landings. The FAA doesn't recognize the area as a runway.