The flight from Martin State Airport near Baltimore to Frederick Municipal Airport takes Lou and Donna Harris only about half an hour in their single-engine Piper Aztec. But they waited 40 minutes just to take off yesterday because of heavy traffic to Frederick.

The fact that Martin State is in one of the restricted flight areas surrounding Washington only added to the hassle. Lou Harris, who lives near Boston, said he was required to submit his planned flight path to the Federal Aviation Administration, only to have the agency change it at the last minute.

"We're under their complete control at that point," he said. "They kind of sent us around."

Their gripe was echoed by many of the thousands of pilots at the 15th annual fly-in and open house yesterday at the Frederick airport. The event was hosted by the Aircraft Owners and Pilots Association, which has more than 400,000 members nationwide and bills itself as the world's largest general aviation organization.

Phil Boyer, the group's president, said security requirements have become burdensome, especially for pilots who live and fly along the East Coast. The association plans to ask for a reduction in the restrictions for smaller planes.

And incidents such as last month's incursion into the high-security no-fly zone around the White House by two lost pilots from Pennsylvania cause unnecessary worry, he said.

"None of that takes away from the stupidity of the pilot," Boyer said. "These people did not make us proud."

Boyer said he spoke with that pilot, Hayden "Jim" Sheaffer, who is a member of the association, last week. Sheaffer apologized, and both men cried, he said. Boyer warned him not to come to the fly-in yesterday for fear of a potential backlash.

"This is what's on everybody's mind right now," he said, referring to Sheaffer's ill-advised flight.

Sheaffer could not be reached for comment yesterday.

Boyer said several pilots have told him they believe that Sheaffer should be put in jail or have his license suspended forever. During a speech yesterday, Boyer got hearty laughs from the crowd when he held up an aerial photo of the Mall and asked, "Is there any confusion as to whereabout you might be?"

Yet pilots said the rules surrounding the capital's restricted airspace can be cumbersome and confusing. Constant radio contact is required, and flight plans can be altered by the FAA midair.

Despite the hassle, about 180 people signed up yesterday for a workshop that would help them receive clearance to fly into the "D.C. 3": College Park Airport, Potomac Airfield and Washington Executive/Hyde Field airport, all within Washington's high-security zone. To get that clearance, pilots must go through additional training, as well as submit to criminal and FAA background checks.

Pilot Andy Rockefeller of Boston said the inconvenience will be worth it. His daughter moved to Georgetown about a year ago. He now lands at Montgomery County Airpark in Gaithersburg -- right on the edge of the no-fly zone -- when he comes to visit her. That means she must drive 45 minutes to pick him up and 45 minutes to bring him back to his plane.

But once he receives clearance, Rockefeller said, he plans to land at College Park and take Metro into the city.

"This will make life a lot easier," he said.

Boyer said that though pilots frequently grouse about the regulations, they tolerate them because they have a passion for flying.

"It's difficult. It's hard," he said. "But these people get in this for a challenge."

Charlie Beliveau has loved planes since he was a boy. Yesterday, his 7-year-old son, Tom, dashed from one of the several dozen planes on display to the next. Tom had helped his dad fold maps during their flight from West Newberry, Mass. He said he wants to get his own pilot's license as soon as he can so he can travel to Texas to buy a pet armadillo.

Beliveau trailed behind his son, letting him explore the planes on his own. And when Tom escaped his watchful eye by climbing inside an Adam Aircraft A500, Beliveau wasn't worried.

"It's not a bad place to be," he said.

Al Kaupa of Severna Park tries on the cockpit of a Diamond aircraft for size at the Frederick fly-in and open house. Kaupa said he is not a pilot yet but is learning. New York pilot Gene Haller is at right. Man in rear is unidentified.