The federal government deems them too dangerous to walk onto a commercial plane, but a hole in the law still allows homegrown threats to man the controls.
A CBS 5 Investigation has learned that nothing is stopping U.S. citizens currently on the no-fly list from learning how to fly.
In the weeks following the attacks on Sept. 11, 2001, the federal government understandably moved to ban foreigners on the no-fly list from enrolling in any type of U.S. flight school.
Most of the terrorists who piloted the planes that horrible day learned how to fly at schools in the United States.
Hani Hanjour, the man believed to be at the controls of the plane that targeted the Pentagon, trained in Phoenix.
A loophole in U.S. Homeland Security still allows those who might have sinister intentions to pilot planes.
They are prevented from being a passenger on a plane or, at best, they must pass through several layers of security before they are ever allowed on board. But if they simply have a driver's license, the federal government allows them to grab the stick and learn how to fly the plane themselves.
Steve Raether has been a flight instructor for more than 20 years.
"In light of incidences like Oklahoma, the Oklahoma bombing, you would think, well, maybe we have some security risks right here at home that we need to be concerned with," Raether said.
Raether points out this risk is probably smaller because the planes students train on are smaller, but the knowledge gained can easily transfer to larger threats like private jets or cargo planes that are not as tightly controlled.
"The basic understanding about pointing an airplane in the right direction is fairly simple," Raether said.
"[The loophole] does need to be closed," Jim Tilmon said. "There's no doubt of that in my mind."
Tilmon is a former commercial pilot and security consultant.
The loophole took him by surprise.
"I think everybody that takes flying lessons should be vetted," Tilmon said. "I don't care who it is. It doesn't matter to me where they are from or what they look like, or male or female, or anything else."
The TSA seems to agree. A statement to CBS 5 News reads, in part:
"At the secretary's direction, TSA is giving consideration to amending these regulations and we will work with the FAA and the FBI to address these concerns."
The TSA did not release a timetable on when that change might happen.
Tilmon said while closing the loophole may seem like a simple matter, he said government agencies are too big to move with the speed this threat requires.
"I don't dream that any system is going to be perfect," Tilmon said. "For every loophole that's closed, we'll discover two more."
The TSA does collect certificates from all flight students and says it scrutinizes them for potential threats, but the students are allowed to undergo training while that vetting process takes place.
Copyright 2012 CBS 5 (Meredith Corporation). All rights reserved.