This segment was originally broadcast on Oct. 8, 2006. It was updated on June 7, 2007.

Anyone who has passed through an airport in the last five years and has been pulled aside for extra screening knows that the government and the airlines keep a list of people they consider to be security threats. Every time you check in at the ticket counter your name is run through a computer to make sure you are not on something called the "No Fly List." It's part of a secret government database compiled after 9/11 to prevent suspected terrorists from getting on airplanes. As correspondent Steve Kroft reports, if your name is on the list or even similar to someone on the list, you can be detained for hours.

It began as a project of the highest priority. In 2003, President Bush directed the nation's intelligence agencies and the FBI to cooperate in creating a single watch list of suspected terrorists. A version of that list is given to the airlines and the Transportation Security Administration to prevent anyone considered a threat to civilian aviation from boarding a plane. The government won't divulge the criteria it uses in making up the list or even how many names are on it. But in the spring of 2006, working with a government watchdog group called the National Security News Service,was able to obtain a copy of the No Fly List from someone in aviation security who wanted us to see what the bureaucracy had wrought.

The first surprise was the sheer size of it. In paper form it is more than 540 pages long. Before 9/11, the government's list of suspected terrorists banned from air travel totaled just 16 names; today there are 44,000. And that doesn't include people the government thinks should be pulled aside for additional security screening. There are another 75,000 people on that list.

With Joe Trento of the National Security News Service, 60 Minutes spent months going over the names on the No Fly List. While it is classified as sensitive, even members of Congress have been denied access to it. But that may have less to do with national security than avoiding embarrassment.

Asked what the quality is of the information that the TSA gets from the CIA, the NSA and the FBI, Trento says "Well, you know about our intelligence before we went to war in Iraq. You know what that was like. Not too good."

"This is much worse," Trento argues. "It's awful, it's bad. I mean you've got people who are dead on the list. You've got people you know are 80 years old on the list. It makes no sense."

60 Minutes certainly didn't expect to find the names of 14 of the 19 9/11 hijackers on the list since they have been dead for five years. 60 Minutes also found a number of high profile people who aren't likely to turn up at an airline ticket counter any time soon, like convicted terrorist Zacarias Moussaoui, now serving a life sentence in Colorado, and Saddam Hussein, who at the time was on trial for his life in Baghdad.

One person who was not surprised is former FBI agent Jack Cloonan, who was retiring from the bureau's al Qaeda task force just as the list was being put together.

"I did see Osama bin Laden on the list both with an "O" in the first name and a "U" in the second name. I was glad to see that. But, some of the other names that I see here, you know, I just have to scratch my head and say, 'My good, look what we've created,'" Cloonan says.

Intended to be a serious a serious intelligence document, Cloonan says the No Fly List soon became a "cover your rear end" document designed to protect bureaucrats and make the public feel more secure.

"I know in our particular case they basically did a massive data dump and said 'Ok anybody that's got a nexus to terrorism, let's make sure they get on the list,'" Cloonan explains. "And once that train left the station, or once that bullet went down range. There was no calling it back. And that is where we are."

The person who oversaw the project is Donna Bucella, who has run the FBI's Terrorist Screening Center since it began operations in 2003. Her group is responsible for evaluating the information submitted by the various intelligence agencies and actually compiling the list.

Asked if she is confident that the list is complete and accurate, Bucella says, "It's like painting a bridge. Once you finish one end, you gotta come back. So we endeavor to get the list as current and accurate and thorough as possible."

"We got a look at the No Fly List from March. And included on that list were 14 of the 19 September 11th hijackers. How do you explain that?" Kroft asks.

"Well, just because a person has died doesn't necessarily mean that their identity has died. People sometime carry the identities of people who have died," she says.

"What you are saying is that you have no information that this person is alive and poses a threat. It's just a name in the database," Kroft asks.

"In order fort the name to get in the data base there has to be information that they are a known suspected terrorist," Bucella says.

"So you are saying it's just a coincidence that there are 14 names in the computer that match the names of 9/11 terrorists. I mean, how do you account for that?" Kroft asks.

Bucella asked how recent this watch list was. When told it was from March, she said, "For some reason the agency might not necessarily want to have taken the name off the list. I can't explain that."

"Also on the list is Francois Genoud, who was a Nazi sympathizer and financier of Arab terrorism. Been dead for ten years," Kroft remarks.

"Well, when you said his - this is what we're doin' a quality review on our watch list," Bucella replies.