• Flight attendants are worried about physical attacks by travelers after an uptick in conflicts over mask mandates, Sara Nelson, international president of the Association of Flight Attendants, told CNBC on Monday.
• The Transportation Security Administration announced Thursday it would double fines for passengers who refuse to comply with the federal mask mandate for air travel.
• Nelson said on "Squawk Box" that flight attendants "overwhelmingly" support vaccine mandates but added that companies would have to include religious and medical exemptions.

Flight attendants enforcing mask mandates onboard are worried about physical attacks from travelers, Sara Nelson, international president of the Association of Flight Attendants, told CNBC's "Squawk Box" on Monday.

The Transportation Security Administration announced Thursday it would double fines for passengers who refuse to comply with the federal mask mandate for air travel. The union president said the TSA's updated policy could help address more mask-related conflicts in the airport, thereby reducing issues for flight attendants to handle on the plane.

"We're concerned every single day when we go to work and put that uniform on, are we the target and going to be punched in the face today," Nelson said.

Flight attendants have long been tasked with policing safety rules and regulations in flight, Nelson said, but they've experienced an uptick in conflicts stemming from mask mandates. The Federal Aviation Administration said July 7 that mask requirements comprised 75% of its unruly passenger complaints since the start of 2021.

Under the TSA's revised fee structure for those who disobey mask mandates, first offenders will face a $500 fine. The agency will levy a $3,000 penalty on anyone who violates the mandate more than once.

When asked whether she would support a vaccine requirement for airline staff and passengers, Nelson said that flight attendants "overwhelmingly" support vaccine mandates. Nelson added that any vaccine mandate would have to include the union's collaboration and the religious and medical exemptions outlined by the Equal Employment Opportunity Commission.

United Airlines and Hawaiian Airlines mandated vaccines for their employees in August, while Frontier Airlines and Alaska Airlines have implemented Covid testing requirements for all unvaccinated personnel. Delta Air Lines has raised health insurance premiums by $200 and implemented weekly Covid testing for unvaccinated employees, and both Alaska Airlines and American Airlines said they would stop paying unvaccinated workers during their Covid quarantines.

"Everyone has got to be vaccinated, and that's the only way that we're going to end this pandemic," Nelson said. "That's the only way we're going to get back to the freedoms that we enjoyed before it started."