The pace of the criminal referrals is slowing, however. The Federal Aviation Administration identified 17 cases it has sent to the FBI in the first three months of this year — mostly for incidents that happened last year but took time to investigate.

Airlines have reported fewer cases of unruly passengers since April 2022, when a federal judge struck down a requirement that people wear masks on planes and public transportation. Before that ruling, about two-thirds of all incidents on planes involved disputes over masks.

The FAA can levy civil fines but lacks authority to file criminal charges, so it refers the most serious cases to the FBI.

“If you act out on a plane, you should just stay at home because we will come after you with serious consequences,” acting FAA Administrator Billy Nolen said in a statement. “We have zero tolerance for unruly behavior.”

The FBI did not say how often it acts on the FAA referrals. Assistant Director Luis Quesada said the bureau is “committed to investigating all incidents that fall within FBI jurisdiction aboard commercial flights” but did not provide numbers.

The FAA announcement came as lawmakers push legislation to create a new no-fly list for people convicted or fined for interfering with flight crews. A similar proposal backed by airline unions failed to gain ground last year in the face of opposition from conservatives and civil libertarians. The current FBI no-fly list is aimed at people suspected of terrorism ties.

The 17 cases that the FAA has referred this year include allegations of assaults against flight attendants and fellow passengers, attempts to open airplane exits during flights, and efforts to break into the cockpit.

In the most recent case, passengers helped subdue a man who, prosecutors say, tried to open an emergency door and attempted to stab a flight attendant with a broken metal spoon during a flight from Los Angeles to Boston.