High-profile incidents involving airline passengers insulting and attacking crew members or refusing to wear masks in defiance of federal requirements risk eroding public confidence in air travel, witnesses and lawmakers said Thursday during a hearing to examine the effects of unruly passengers on the aviation system.

Federal agencies have stepped up efforts to quash such behavior, but even as the Federal Aviation Administration said Thursday that the rate of reported incidents has declined since the start of this year, it conceded that such occurrences remain unacceptably high.

The hearing before the House subcommittee on aviation is Washington’s latest response to a sharp rise in mask-related incidents and bad behavior on airplanes. It comes after stepped-up enforcement and increased fines, with lawmakers this week questioning whether changes have deterred conflicts.

On Thursday, Rep. Rick Larsen (D-Wash.), chairman of the subcommittee, said incidents have put the safety of front-line workers, passengers and the aviation system at risk.

“As the nation works to get to the other side of the covid-19 pandemic, the surge in public air rage incidents has exacerbated the already-tenuous workforce situation in our aviation sector and eroded confidence in air travel,” he said.

Added Rep. Garret Graves (La.), the top Republican on the subcommittee: “It needs to be a civil experience for everyone on the plane, and obviously there are additional safety considerations for being tens of thousands of feet up in the air in a metal airplane when thinking about this.”

The FAA said this week it has received 4,385 reports of unruly passenger incidents, most of which involve masks. The numbers have prompted both chambers on Capitol Hill to voice concerns about airplane behavior.

In separate letters sent to FAA Administrator Stephen Dickson and Attorney General Merrick Garland, Senate Transportation Committee Chair Maria Cantwell (D-Wash.) and Senate Judiciary Committee Chair Richard J. Durbin (D-Ill.) said this week that existing deterrent measures have been ineffective. They suggested that stiffer penalties, including criminal prosecution, should be used to reinforce a message that bad behavior is unacceptable — an approach that many at Thursday’s hearing endorsed.

The FAA said it has launched 789 investigations this year, more than double the number for 2019 and 2020 combined. The agency has begun enforcement actions in 162 cases and proposed more than $1 million in fines. About three-fourths of cases involve a passenger refusing to wear a mask.

The FAA said Thursday the number of incidents has fallen since the zero-tolerance policy launched, but remains too high.

As of last week, the agency said unruly passenger incidents were occurring about six times for every 10,000 flights. That’s a roughly 50 percent decline from earlier this year, but more than twice as high as the end of 2020.

During Thursday’s hearing, witnesses at the receiving end of poor passenger behavior told the panel the impact of encounters stretches beyond the moment and can leave them rattled months later.

Teddy Andrews, an American Airlines flight attendant testifying on behalf of the Association for Professional Flight Attendants, recalled what happened when he stepped in to intervene after a passenger refused a request from another flight attendant to wear a mask. When Andrews reminded the traveler about the rule, the man responded by repeatedly calling him a racial epithet. The passenger eventually complied, but Andrews said he was shaken.

The FAA has had a zero-tolerance policy in place since January. Earlier this month, the Transportation Security Administration — which enforces a mask mandate in transportation settings — doubled fines for those who refuse to comply. Lawmakers and witnesses at the hearing praised those efforts but said there is room to do more, including stepping up prosecution of the most egregious cases by the Justice Department.

“We need DOJ criminal charges and enforcement, we need to make the FAA zero-tolerance policy permanent and we need to staff up investigators and extend investigation time,” said Sara Nelson, international president of the Association of Flight Attendants-CWA.

Rep. Peter A. DeFazio (D-Ore.), chairman of the House Transportation and Infrastructure Committee, said the rate of incidents is too high, adding that federal regulators need more resources to bring the numbers down.

“The FAA inspectors who handle these cases are also responsible for conducting oversight and surveillance of the aviation system’s safety,” he said. “They can’t continue without some relief.”

While most complaints the FAA receives involve face masks, unruly behavior is often fueled by alcohol. DeFazio noted that several airports advertise “to-go” cups, and pressed Christopher Bidwell, senior vice president for safety at the Airports Council International-North America, about why the practice is allowed.

“Much has been discussed in the press about the role of alcohol in the behavior of unruly passengers, but we have yet to see data on the number of incidents that involve alcohol,” Bidwell said.

Several Republican members of the subcommittee raised concerns about how airlines handled issues involving travelers who are disabled or families with children who are unable to wear masks.

“I don’t think that Americans with disabilities are really aware of these exemptions, and I know that many of them feel discriminated, discriminated against right now,” said Rep. Pete Stauber (R-Minn.) “What is the protocol that a flight attendant currently goes through when dealing with a passenger who has an exemption?”

Nelson said travelers should try to seek such exemptions when they book their tickets to avoid confusion at the gate.

“It’s very important that the airlines are making it very clear at the point of ticket sales for anyone who needs to provide information to the airline ahead of time about these challenges,” she said. “This does already exist. It is already in the ticketing process.”

Meanwhile, federal regulators say they continue to work on new strategies for deterring such behavior.

Senior leaders at the FAA met Thursday with representatives of U.S. airports to discuss how to reduce unruly passenger incidents. It follows a meeting Tuesday, when FAA officials met with representatives from U.S. airlines, telling them they have one month to develop steps to curb behavior problems.

Flight attendants and crew members around the country are training in self-defense with federal air marshals. (Monica Rodman/The Washington Post)

The agency said it plans to hold similar meetings with unions and other affected groups in the coming days.

“As partners in aviation safety, we will not tolerate violent and unruly behavior on planes or at airports, no exceptions,” the FAA said in a statement this week. “Our collective and coordinated actions will ensure a safe experience for passengers and protect our crew members and employees from unlawful interference.”

The TSA, which has separate enforcement authority, reported this month that since a mask requirement went into effect in February, it has received more than 4,000 reports of mask-related incidents. The agency said it is pursuing possible fines in 126 incidents. The TSA did not detail how many of those incidents took place on an airplane or in other transportation settings.