(CNN) — Authorities have received more than 3,000 reports of unruly airplane passengers this year, and the majority of those involve face mask rules, the Federal Aviation Administration told CNN on Monday.
The sharp spike in misbehaving and even violent passengers includes 2,300 reports that passengers refused to comply with the federal requirement to wear face masks on airplanes. The mandate also applies to other modes of public transportation such as buses.
The latest high-profile unruly passenger was an off-duty Delta Air Lines flight attendant who allegedly used the plane's intercom system and assaulted two other flight attendants. The pilot called for "all able-bodied men please come to the front of the plane for an emergency," and the off-duty flight attendant -- allegedly wearing a helmet and elbow pads -- was subdued.
The FAA said it has identified potential violations of federal rules so far in 465 of the 3,000 cases reported and has begun enforcement action in 57 cases. In a normal year, it has taken action in as many as 150 cases of passengers violating FAA rules.
FAA Administrator Steve Dickson in January launched a zero-tolerance policy against passenger misbehavior after the agency observed a dramatic increase in reports. Officials began tracking the number of reported instances of unruly passengers -- something they never did before.
Dickson told CNN in an interview last month he is "concerned" about the increase in unruly passengers and the safety risk the problem poses to flights.
"The aviation system that we have in the United States is the safest form of travel in human history," Dickson said. "That's what this zero-tolerance policy is all about -- to make sure that we get this situation under control."
The agency has publicly released details of 23 incidents, and announced proposed fines totaling more than $400,000.
The largest single fine was proposed in May as $52,500 against a passenger who the agency said "tried to open the cockpit door, repeatedly refused to comply with crew members' instructions, and physically assaulted a flight attendant by striking him in the face and pushing him to the floor." Flight attendants and another passenger restrained that unruly passenger, but he "freed himself from one of the handcuffs and struck the flight attendant in the face a second time."
Sara Nelson of the Association of Flight Attendants labor union said Sunday on CNN that the situation is "out of control."
"We are hearing from flight attendants who are saying I'm concerned about going to work now," she said. "This is so pervasive in our workplace that I'm concerned about going to work -- I'm actually afraid to go to work."