A brazen scheme in which guns — even an AK-47 rifle — were taken onto passenger jets for years in carry-on luggage was described by a Brooklyn prosecutor Tuesday as a terrorism threat that should cause the airline industry to end the practice of letting some workers enter airports without security screening.

"I hope this is a wakeup call for the nation," Brooklyn District Attorney Kenneth Thompson said at a news conference. "This was an egregious breach of our nation's air traffic security."

Thompson's comment came as he described a case brought against five people, including an airline baggage handler who was charged a day earlier by federal authorities in Atlanta.

Thompson said he was not trying to scare anyone. But he said it's "truly frightening" what investigators learned after a probe that started as a way to reduce gun violence in Brooklyn.

He said Mark Quentin Henry, 45, who was fired by Delta Air Lines in 2010 after three years for abusing its buddy pass system, took guns aboard at least 17 commercial airliners this year as they traveled from Atlanta to both New York City airports.

The prosecutor said Henry was given the guns, sometimes in airport restrooms, by Eugene Harvey, 31, an Atlanta baggage handler who worked for Delta before he was fired as a result of the investigation.

Three others were arrested on gun charges in the probe.

Henry's lawyer, Terence Sweeney, said his client, held without bail, "maintains his innocence and he's looking forward to his day in court."

Henry was arrested Dec. 10. Investigators videotaped him in the Atlanta airport prior to a morning flight to Kennedy International Airport in New York, where he was videotaped leaving the airport and was followed to his residence in Brooklyn.

Thompson said when Henry was confronted by investigators, he said there were guns in a knapsack in his apartment.

"He said: 'I just brought them from Atlanta on the plane. He made that admission," Thompson said.

The prosecutor said investigators discovered that guns were individually wrapped and that ammunition was in the bag next to them "that he could have just put together and started shooting."

He said the scheme "really poses a threat in terms of terrorism."

"They can put guns on a plane, they could easily have put a bomb," Thompson said.

Thompson said 153 guns, almost all of which were bought in Georgia, were seized during the seven-month gun trafficking probe, which led investigators to Henry and his frequent flights between Atlanta and New York.

The prosecutor said investigators believe he has been transporting guns on planes for at least five years, using companion passes available because his mother had worked for airlines for years before retiring.

On Dec. 10, Henry flew with 16 weapons, including four 9mm pistols, a .380-caliber pistol and ammunition and magazines, Thompson said. The prosecutor said he flew with the AK-47 in November.

He said it was likely he chose airplanes for the speed and ease of the travel.

"We didn't know for sure that he was transporting guns on a plane until Dec. 10," Thompson said, though he added that Delta was notifying investigators each time Henry boarded a plane.

Delta spokesman Morgan Durrant said Delta has cooperated with authorities.

"We take seriously any activity that fails to uphold our strict commitment to the safety and security of our customers and employees," he said.

In a statement Tuesday, Hartsfield-Jackson Atlanta International Airport spokesman Reese McCranie called safety and security its "highest priority."

He said all employees must pass extensive criminal history record checks, security threat assessments, and security training prior to being approved for access to secured areas and employees are subjected to continuous vetting and random inspections.

"In light of these recent events, we are reviewing the security plan and will make the appropriate changes to prevent future incidents of this nature," McCranie added. The airport is considered among the world's busiest.

The Transportation Security Administration, which is responsible for screening airline passengers, said in a statement that it takes "potential for insider threats at airports very seriously."

It said security threat assessments and airport criminal checks made before people are hired is an ongoing process that includes random checks.

"TSA continues to closely partner with law enforcement on this investigation and, where possible, will use the findings from the investigation to improve current processes," it said.