More than three years after the 2001 attacks, at least 25 alleged illegal aliens - including four from countries where the U.S. says there's terrorist activity - were able to get jobs maintaining commercial jets in North Carolina. The workers passed criminal background checks and Social Security screenings. And six held the Federal Aviation Administration's top mechanical certification, allowing them to clear airplanes to return to service.
Just how frightened people should be of last month's roundup of 27 workers at TIMCO Aviation Services is open to debate.
But some in the industry said it shows the security loopholes in the growing outsourcing of aircraft repairs.
As much as half of the servicing of the nation's airliners is now outsourced to third-party vendors whose mechanics are not required to be certified, or to have the extensive FBI background checks done on in-house airline mechanics.
Most of those arrested came from Central and South America. But four came from Sudan and the Philippines - countries on a Department of Homeland Security watch list for potential terror links.
"Any time we have individuals working at critical infrastructure locations, like airports, that are not who they say they are and may be utilizing fraudulent documents, it does pose a potential security threat," said Dean Boyd, a spokesman for the U.S. Immigration and Customs Enforcement Agency.
Word of the roundup comes as two studies have found that airport security is no better than it was before the 9/11 terror attacks, despite billions of dollars spent by the federal government, according to congressional officials briefed on the findings.
The studies - one by congressional investigators and the other by the Homeland Security Department - found major problems with the screening of airline passengers at the nation's 450 major airports.
In the months after the 9/11 attacks, the Transportation Security Administration was created and took over airport security.
More than 45,000 new workers were hired and new restrictions were put in place.
But officials say the TSA's efforts have proved disappointing.
"It's not the level of performance we need in terms of protecting the public and the aviation system," said Rep. Peter DeFazio (D-Ore.), the ranking Democrat on the aviation committee who was briefed on the studies.
DeFazio said the problem isn't the TSA employees - who he says are better trained and more professional than the private workers who used to handle security. It's the technology, he said.
"They are using the same 1980s equipment," he said of the baggage X-ray machines. He said the solution is to buy more sophisticated machines.