For more than a year and a half, Rep. John Lewis has endured lengthy delays at the ticket counter, intense questioning by airline employees and suspicious glances by fellow passengers.

Airport security guards have combed through his luggage as he stood in front of his constituents at the Atlanta airport. An airline employee has paged him on board a flight for further questioning, he said. On at least 35 occasions, the Georgia Democrat said, he was treated like a criminal because his name, like that of Sen. Edward M. Kennedy (D-Mass.), appeared on a government terrorist watch list.

While Kennedy managed to get security officials to end his airlines hassles after three weeks of trying, Lewis had no luck for months. Then he found his own way around the security mess.

Lewis added his middle initial to his name when making his airline reservations. The computer system apparently didn't flag tickets for "Rep. John R. Lewis," and the hassles suddenly ended.

"The 'R' is the only thing that has been saving me," Lewis said from Atlanta yesterday.

Hundreds of passengers -- possibly thousands -- have contacted the Transportation Security Administration complaining that the government's secret watch lists are unfairly targeting innocent travelers and causing travel headaches. Just last month, more than 250 passengers sought to be removed from the list.

But even more disconcerting, some of these travelers and security experts say, is that the system can be easily circumvented by a simple adjustment to one's name. "The no-fly list assumes that dangerous people are going to use the same name the government thinks they use. If I'm Osama bin Laden, I'm going to use a fake ID when I go on an airline and hijack it," said Aaron H. Caplan, attorney at the American Civil Liberties Union. "The whole notion that keeping a list of names contributes to safety is kind of questionable, especially when terrorists use aliases all the time."

Some passengers who were told that their names matched others on the watch lists said they have been tipped off by airline employees who were embarrassed and apologetic about having to delay them when the passengers were known to the employees.

John W. Lewis, a 76-year-old doctor who lives in Camden, Maine, said he was stopped and questioned before several Continental Airlines flights to Houston, where he teaches a course. When he arrived for his usual flight in June, airline agents had some advice for him. "They said, 'You're not on the list, but your name is, and if you change your name, it will be okay,' " Lewis said.

So he changed the name on his credit card and his airline tickets to "Dr. John W. Lewis," but it has not eliminated the problem entirely, he said. Airline agents still stop him when he checks in at the ticket counter, he said. But no one raises any questions on the return trip. He said he has contacted Maine Sen. Susan Collins (R) and Rep. Lewis to try to fix the problem permanently. "I can't believe we are all on the hit list," he said, referring to people named John Lewis.

The no-fly list is a collection of names from the FBI and intelligence agencies that is managed by the TSA and delivered to airlines. Each airline has its own system for matching the names. A Department of Homeland Security official said that Kennedy and Rep. Lewis were not on the no-fly list but that similar names had popped up on another, more extensive airline terrorist watch list.

Security experts said the government's no-fly list and other watch lists of known terrorists come up with false matches because they are based on antiquated technologies and are unevenly administered by airline employees instead of security personnel.

"What is flawed in the identification system is the administration of this list," said TSA spokeswoman Yolanda Clark. The agency is working to replace the existing system with one that is more ambitious, but it is not clear when it will be ready. "Airlines have different policies and procedures," she said.

Several airlines said privately yesterday that they find it uncomfortable enforcing a security policy created by the government, especially when they have to tell some of their best customers -- frequent fliers -- that they are on a watch list. Several carriers declined to comment on experiences by passengers.

Douglas R. Laird, an aviation security consultant who helped develop another government computer screening system, said the no-fly list is "pretty much worthless."

"Name search [systems] were relatively unimportant for the simple reason that you don't have to do much to throw the computer off," Laird said.

But other security experts disagree and say that even though it is impossible to eliminate false positives -- that is, cases like that of John Lewis -- watch lists can potentially stop a terrorist if they are handled correctly. Billie Vincent, a former Federal Aviation Administration official, said the government needs to simplify and streamline its lists and address tricky problems such as how to handle Arabic names, which can be spelled a number of different ways. "We do need to compile and use the lists in addition to other layers of security," Vincent said in an e-mail.

The TSA said that last month, 258 passengers filled out forms requesting to be removed from the government's watch lists. It said it could not say how many to date have made similar requests or actually ended list-related hassles. Once a passenger submits additional identification such as a birth certificate or passport to the agency, the TSA sends updated information to the airline and a verification letter to the passenger. The TSA warns, however, that even when a traveler arrives at the airport with the letter, delays may still occur.

Rep. Lewis said that he filled out the form and received a letter from TSA that verifies his identity but that he doesn't want to use it. "I'm not sure why I would have to go around carrying something like a pass," said the congressman, who is known for his civil rights record. "It reminds me of South Africa."

Rep. John Lewis, here with Teresa Heinz Kerry, now uses his middle initial to book tickets.