If Delta Air Lines gets its wish, unruly passengers could be blackballed by multiple carriers.

Delta executives said in pair of memos to employees Thursday that the airline’s permanent “no fly” list has grown to more than 1,600 people and that it has asked other carriers to share their lists with it.

“As we all know, a list of banned customers doesn’t work as well if that customer can fly with another airline,” Eric Phillips, Delta’s senior vice president of airport customer service and cargo, wrote in one of the memos.

“Let me be clear that any unruly customer behavior, and harmful actions against our team members, will not be tolerated,” Phillips continued. “Anytime a customer physically engages with intent to harm, whether in a lobby, at a gate or onboard, they are added to our permanent No Fly list. 

Such a shared “no fly” list would be different from the longstanding government No-Fly List aimed at preventing potential terrorists from boarding planes and entering the United States. 

The Delta memos were sent on the same day a House Transportation subcommittee held a hearing on the alarming rise of cases involving disruptive airline passengers.

From January and September 2021, the Federal Aviation Administration has logged 4,284 unruly passenger reports and 3,199 mask-related incidents. The agency initiated 789 investigations and more than 160 law enforcement cases as a result of those incidents and proposed more than $1 million in fines against disruptive passengers.

Sara Nelson, the international president of the Association of Flight Attendants union, told lawmakers that if incidents continue at the current level, it “may result in more incidents in 2021 than the entire history of commercial aviation.”

In January, the FAA instituted a zero-tolerance policy, and the Transportation Security Administration earlier this month doubled fines for individuals who fail to comply with its mask mandate on commercial flights.

It’s not clear whether other airlines will go along with Delta’s proposal to share their “no fly” lists.

In a statement to Spectrum News, Southwest Airlines spokesman Chris Mainz said that, as a matter of policy, the company does not publicly disclose the details of its restricted fly list.

“That said, we continue to work with our unions, with other airlines, and with the FAA to brainstorm ways to further prevent unruly situations and conflict escalation, including sharing best practices with other airlines,” Mainz said. “We have made it clear we will not tolerate violent and unruly behavior on planes or at airports, no exceptions.”

United Airlines did not respond to a request for comment. American Airlines directed questions to Airlines for America, the trade group representing major U.S. carriers.

Airlines for America did not directly address the issue of carriers sharing their "no fly" lists but added that it is working with federal agencies "to identify additional actions that can be taken across the aviation ecosystem to prevent and respond to unruly passenger incidents." The group also is advocating for increased and expedited prosecution of disruptive passengers by the Justice Department.

This article was updated with Airlines for America's statement.