(NewsNation) — The Department of Homeland Security (DHS) has diverted U.S. air marshals to the southern border to support overwhelmed federal agents but some fear the move will endanger the skies during the nation’s holiday travel season.

“The DHS Secretary is taking hundreds of FAMs (federal air marshals) out of the skies during the busiest travel season and during a time when terrorists have attempted to attack the homeland no so long ago,” David Londo, the president of the Air Marshal National Council (AMNC), wrote in a letter to President Joe Biden earlier this month.

Londo said air marshals — many of whom are being asked to perform non-law enforcement duties at the border — already face an arduous flight schedule that has contributed to some of the highest rates of divorce and suicide across law enforcement.

The Federal Air Marshal Service (FAMS) was created in 1961 to counter hijackers, but the program was significantly expanded after the September 11 terrorist attacks in 2001.

On 9/11, there were just 33 air marshals operating on U.S. flights. Today, there are an estimated 3,000, although the exact number is unknown.

“These ground-based duties that they’re pulling us out of the sky to go to the border are just demolishing our chances at stopping another 9/11,” Sonia Labosco, the executive director of the AMNC, said in an interview with Fox News this week.

Each day there are about 45,000 flights handled by the Federal Aviation Administration’s (FAA) air traffic controllers, and Labosco said air marshals are now on less than 1% of them because of the border policy.

Under normal circumstances, Labosco said air marshals are on “at least 5% of flights.”

A retired supervisory federal air marshal also shared his concerns about the White House plan.

“First, the border isn’t secure. And now the airplanes aren’t secure,” Frank Terreri said, later adding, “By taking all these extra assets, bringing them down to the border, doing menial tasks to support the Border Patrol that’s not supported in the first place – makes no sense. This pretty much puts passengers at risk, meaning their flights, especially during this heavy holiday season, aren’t covered.”

The plan has also drawn criticism from some members of Congress.

“DHS is removing hundreds of air marshals from the skies during one of the busiest travel seasons of the year, even though you have stated America’s aviation infrastructure is a very high threat and is a target,” Rep. Jefferson Van Drew, (R-NJ) said.

In an email to NewsNation, DHS rejected the assertion that flights are being left unprotected, calling it “completely false.”

“Federal Air Marshals have long supported various Departmental operations on a regular basis across Democratic and Republican administrations alike,” a DHS spokesperson said via email. “There is nothing new or unique about this.”

A separate NewsNation source within the FAMS said the 1% claim “seems a little extreme.” DHS did not answer a question regarding what percentage of flights have air marshals on them.

DHS pointed out that the Trump administration also temporarily deployed federal air marshals to the southern border back in 2019.

There’s some evidence to support the argument that flights have become more chaotic in recent years.

Since the COVID-19 pandemic, the number of unruly passengers reported to the FAA has skyrocketed. In 2021, the FAA investigated 1,099 incidents compared to just 146 in 2019.

This year, the FAA has initiated 767 investigations with one of the busiest travel months still to come.

Last week, a Utah man on a JetBlue flight from New York to Salt Lake City was arrested after holding a straight-edge razor blade to a woman’s neck.

In a separate incident earlier this month, a Frontier Airlines flight was forced to make an emergency landing after a passenger was found in possession of a box cutter.

But it’s not clear whether having more air marshals helps curb misbehavior since the federal agents are primarily concerned with terrorist threats and are strategically deployed on routes deemed high risk.

DHS did not respond to a question asking how many arrests air marshals make in a given year.

The diversion to the southern border comes after Customs and Border Protection logged a record-breaking 2.3 million encounters with illegal migrants in the 2022 fiscal year. 

Many fear that the situation is about to get worse now that Title 42, a pandemic-era policy that allowed agents to turn away migrants, is set to end.

Biden has not declared a national emergency at the border after terminating former President Donald Trump’s emergency declaration on his first day in office.