As airlines try to persuade Americans to fly again, they have touted their policies for keeping passengers safe, including the requirement that everyone onboard a plane wear a mask.

But travelers on recent flights said the rules were not being enforced. And flight attendants said they had been told not to confront passengers who opted to not follow them.

Drusilla Lawton flew from South Carolina to Wyoming in May on two American Airlines flights and said the mask rule was not being enforced during boarding or on the plane. “I was just horrified watching the gate agent let people through without their masks,” said Lawton, a part-time portfolio manager. “When I was walking down the aisle I was wondering, ‘How many people aren’t wearing a mask?’ There were so many.”

Lawton said that the first leg of the trip was “particularly bad” and that the people across the aisle from her, those in front of her and those behind her did not wear masks. Although the woman sitting next to her put on a mask after Lawton asked her to, there was never an announcement from the flight crew or captain about the rules.

On social media and in emails to The New York Times, other travelers described similar scenarios, which left them feeling they had to choose between confronting fellow passengers and possibly encountering hostility, and sitting on a flight for hours potentially being exposed to the coronavirus.

The patchwork enforcement of policies has left passengers uncomfortable, confused about whether they should be wearing masks and concerned about their safety. They’ve also left flight attendants with the difficult task of trying to make people do something they won’t be punished for if they choose not to comply.

“Airlines have said follow the guidelines but don’t enforce them, don’t tackle people to the ground and don’t turn flights around if they don’t listen,” said Sara Nelson, president of the Association of Flight Attendants union. “That gets around to the public, then it’s, ‘I don’t have to do this. There are no consequences if I don’t do this.’ That, too, can lead to conflict, not just with the flight attendants but with other passengers, who get angry, and all of a sudden we have to break up a fight.”

Nicole Carriere, a spokeswoman for United, said that face coverings are mandatory for all employees and passengers onboard and that the airline is providing free masks to customers who need them. In instances where people refuse to wear a mask, they can be pulled aside “to further understand their concerns and discuss options,” Carriere said. “This would include things like moving them to a new seat where they could maintain a safe social distance from other passengers.”

Denying someone boarding would be a “last resort,” she said.

TYPICALLY, when an event as major as the coronavirus is involved, government agencies, including the Federal Aviation Administration, the Department of Transportation, the Department of Labor and the Occupational Safety and Health Administration, come together with airlines, unions and other stakeholders to create policies and emergency procedures to help travelers and transportation staff, said Nelson of the flight attendants union.

But since the coronavirus pandemic began, no such coordination has taken place. That has left the airlines to set their own rules — and their own standards of enforcement.

Lisa Hanna, a spokeswoman for Delta, said that the airline is requiring people to wear masks “beginning in the check-in lobby and across Delta touchpoints, including Delta Sky Clubs, in jet bridges and onboard for the duration of the flight — except during the food and beverage service. A face mask is required to begin the boarding process and also strongly encouraged in high-traffic areas.”

Ross Feinstein, a spokesman for American, said that “American, like other U.S. airlines, requires customers to wear a face covering while on board, and this requirement is enforced at the gate while boarding. We also remind customers with announcements both during boarding and at departure.”

But Tony Scott said that was not the case. The 53-year-old marketing executive who lives in Los Angeles, booked a first-class ticket on the airline, expecting that with social-­distancing policies he would have adequate space. But the passenger next to him, a teenage girl, refused to wear one. When he talked to the flight attendant, he was told that masks were optional, even though the American app said otherwise. The flight attendant later told Scott that masks were mandatory but not for children.