The Federal Aviation Administration is appealing to airports to discourage the sale of “to-go” alcohol and to take a more active role in helping to curb a rise in assaults on flight attendants.

In a letter to the leaders of about 1,000 commercial airports nationwide, FAA Administrator Steve Dickson said the agency is doing all it can to address a surge in unruly behavior on planes, “but we need your help.” The FAA said this week that it had received 3,715 reports of unruly passengers in 2021, with more than 70 percent of the incidents related to a federal mask requirement on planes to prevent the spread of the coronavirus.

Dickson said agency investigations have shown the impact of alcohol on passenger behavior.

FAA regulations prohibit consuming alcohol onboard that is not provided by the airline. Some airlines aren’t serving alcohol during the coronavirus pandemic, prompting passengers to carry their own.

“We have received reports that some airport concessionaires have offered alcohol ‘to-go,’ and passengers believe they can carry that alcohol onto their flights or they become inebriated during the boarding process,” Dickson wrote. “The FAA requests that airports work with their concessionaires to help avoid this.”

Every week, Dickson said, law enforcement officers are called to meet problem passengers at airport gates. Even after assaults are reported, “many of these passengers were interviewed by local police and released without criminal charges of any kind,” Dickson wrote. “When this occurs, we miss a key opportunity to hold unruly passengers accountable for their unacceptable and dangerous behavior.”

The FAA letter, dated Tuesday, comes as flight attendants continue to push for more federal help. Last month, the Association of Flight Attendants-CWA released a survey of nearly 5,000 flight attendants describing the depth of problems they face on the job.

As more people start flying again, airlines are seeing a big jump in disruptive behavior and cases of unruly passengers. So why is it happening? (Lee Powell/The Washington Post)

Nearly 1 in 5 flight attendants reported experiencing a “physical incident” with an unruly passenger this year, according to the online survey. That could include a push, slap or any other body-on-body interaction, according to the union.

Federal court records show the interactions range from flicking away a flight attendant’s tap on a shoulder to punches in the face. The union called the finding that 17 percent of its members faced physical incidents “shocking.”

The agency in January instituted a “zero-tolerance” policy toward passengers interfering with crew members, which already is against federal law.

The flight attendants union said the policy has proved insufficient to address the scale of the problem, but called for it to be made permanent as part of further efforts to stem disruptive behavior. Union President Sara Nelson said her organization would provide the survey’s findings to the FAA, the Department of Transportation, the FBI and the Transportation Security Administration “to help more fully identify the problems.”

“This is not a ‘new normal’ we are willing to accept,” Nelson said. “The vitriol, verbal and physical abuse from a small group of passengers is completely out of control.”

In a statement, the FAA said the agency “shares the concerns of the Association of Flight Attendants, and we’re deeply troubled any time a cabin-crew member faces threats while performing their critical, safety duties.” The statement pointed to the agency’s zero-tolerance policy, which it noted has been welcomed by flight attendants.

Under FAA policy toward passengers interfering with crew members, agency safety inspectors are required to fill out investigative reports that could lead to sanctions such as fines. Previously, the FAA might have relied on warning letters or counseling to deal with problem passengers.

“We are taking the strongest possible action within our legal authority,” the agency said.