As the man returned from the lavatory with a mask dangling from one ear, a flight attendant asked him to put it on properly.

“Why? Is something going on that I should know about?” the passenger asked, before grabbing the mask and ripping the string. “Damn it, I guess I can’t wear it now.”

Other passengers have verbally abused and taunted flight attendants trying to enforce airline mask requirements, treating the potentially lifesaving act as a pandemic game of cat-and-mouse. A loophole allowing the removal of masks while consuming food and beverages is a favorite dodge.

Asked to mask up, one passenger pulled out a large bag of popcorn and nibbled her way through it, kernel by kernel, stymieing the cabin crew for the length of the flight. Others blew off requests by chomping leisurely on apple slices, between occasional coughs, or lifting an empty plastic cup and declaring: “I am drinking!”

The displays of rule-bucking intransigence are described in more than 150 aviation safety reports filed with the federal government since the start of the pandemic and reviewed by The Washington Post. The reports provide an unguarded accounting of bad behavior by airline customers, something executives hit by a steep drop in travel and billions in pandemic-related losses are loath to share themselves.

Some reports raise safety concerns beyond the risk of coronavirus infection. A flight attendant reported being so busy seeking mask compliance that the employee couldn’t safely reach a seat in time for landing.

One airline captain, distracted by mask concerns, descended to the wrong altitude. The repeated talk of problem passengers in Row 12 led the captain to mistakenly head toward 12,000 feet, not a higher altitude given by air traffic control to keep planes safely apart. The error was caught, and “there was no conflicting traffic,” the captain wrote.

Some passengers are portrayed as oblivious, obstinate, foul-mouthed and, at times, dangerous. One called a flight attendant a “Nazi.” Another “started to rant how the virus is a political hoax and that she doesn’t wear a mask,” a flight attendant reported.

With millions of passengers ignoring warnings from the Centers for Disease Control and Prevention to refrain from holiday travel, the reports offer an X-ray into the country’s deeper failures against the coronavirus — and insights into the pitfalls and possibilities facing a new presidential administration.

While the White House under President Donald Trump has, at times, been dismissive or hostile toward masks, President-elect Joe Biden is making a patriotic appeal to “mask up for 100 days,” whatever people’s politics. Biden has said he will sign an order on his first day requiring masks for “interstate travel on planes, trains and buses.” How well those efforts will work remains to be seen.

Experts in psychology and decision-making say hostility toward wearing masks, even within the shared confines of a passenger jet, has been fueled by politicization — but also by skewed incentives and inconsistent messaging.

“The reinforcement principles are backward,” said Paul Slovic, who studies the psychology of risk at the University of Oregon.

The usual signs of danger, and rewards for following potentially bothersome rules, are thrown off by a virus that is spread easily by people who don’t know they have it, Slovic said.

“You get an immediate benefit for not following the guidelines because you get to do what you want to do,” Slovic said. “And you don’t get punished for doing the wrong thing” because it’s not immediately clear who is being harmed.

The “squishiness of the requirement” to wear masks on planes also undermines the message that they are critical for public health, Slovic said. In contrast, he cites the rigid clarity of the ban on flying with a firearm. “It’s not, ‘You can carry it as long as you don’t use it,’ ” Slovic said.

But passengers are allowed to drop their masks to snack and sip beverages. “When you start opening it up to eating, the whole thing kind of weakens,” Slovic said.

Applying mask rules also worsens the already strained position of flight attendants, who are front-line enforcers even as they keep their usual safety responsibilities, experts said.

“Flight attendants are dealing with mask compliance issues on every single flight they work right now,” said Taylor Garland, spokeswoman for the Association of Flight Attendants-CWA, noting that those efforts range from friendly reminders to facing passengers “actively challenging the flight attendants’ authority.”

The Department of Transportation in October rejected a petition to require masks on airplanes, subways and other forms of transportation, with Secretary Elaine Chao’s general counsel saying the department “embraces the notion that there should be no more regulations than necessary.”

The nation’s aviation regulator has deferred to airlines on masks, with Federal Aviation Administration chief Stephen Dickson telling senators at a June hearing “we do not plan to provide an enforcement specifically on that issue.”

Such matters are more appropriately left to federal health authorities, Dickson argued. “As Secretary Chao has said, we believe that our space is in aviation safety, and their space is in public health,” Dickson said, referring to the CDC and other health officials.

Airline representatives say they take mask usage seriously and the overwhelming majority of customers comply. Some airlines have banned passengers for the length of the pandemic for refusing to mask up. Many have eliminated medical exemptions in their mask requirements.

“Of the hundreds of thousands of passengers who have flown with us, we have only needed to ban about 370 customers for not complying,” United Airlines spokeswoman Leslie Scott said. Delta said its mask-related no-fly list includes about 600 people, despite carrying about 1 million people each week.

Resistance by some passengers prompted Alaska Airlines to begin issuing yellow cards, akin to the warnings in soccer, to problem passengers.

The initial yellow card said employees would file a report that could result in a passenger being suspended. A later version was more aggressive, saying continued defiance would lead to a flight ban “immediately upon landing,” even if the customer had a connecting flight.

Alaska Airlines has barred 237 passengers since August, and “in more than half of these incidents we also canceled onward or returning travel,” spokeswoman Cailee Olson said.

American Airlines declined to release numbers of banned customers, as did Southwest, which said in a statement it appreciates “the ongoing spirit of cooperation among customers and employees as we collectively take care of each other while striving to prevent the spread of COVID-19.”

Yet a small, uncooperative minority can wreak outsize havoc, safety reports show.

The anonymous reports are collected in a National Aeronautics and Space Administration database, part of a program meant to increase aviation safety by encouraging employees to provide candid descriptions of emerging problems without fear of reprisal. Names of people filing the reports, and their airlines, are removed by NASA before they are made available to regulators at the FAA and the public.

NASA analysts screen the reports to weed out irrelevant filings and may call back filers to clarify safety points. But its analysts do not try to verify people’s identities or the accuracy of the reports.

The database shows some fliers treat airline mask requirements as a seemingly asinine rule to evade, akin to sneaking a late look at text messages after phones are supposed to be in airplane mode. Passengers berate fight attendants about their noncompliant cabin mates. Some reports read like cries for help.

“It all has to stop,” pleaded one flight attendant.

“In the future I would like to feel safe while doing my job,” said another.

Among the incidents:

— A woman refused to wear her mask as the plane rolled away from the terminal, saying it made her ill, and the pilot pulled over temporarily to try to avoid returning to the gate. She continued to resist but finally agreed.

“As soon as we took off, she took it off again and kept it off the entire flight,” the flight attendant reported.

— A man started down the aisle, pausing about 18 inches from a flight attendant.

“He sneezed directly in my face, making no attempt to cover his mouth, pull up his mask or turn towards the row 1 window,” the employee wrote. The flight attendant, who was wearing a face covering, judged the act unintentional and tried to blot away the remnants.

— A woman propped her foot up and painted her toenails with her mask below her chin, despite several requests to wear it properly. After another passenger appealed for more to be done, the woman acquiesced, then loudly instructed the flight attendant to “go away!”

After landing, she cut in line to rush off the plane. “Although we understand the importance of wanting to retain customer loyalty, this kind of behavior should not be tolerated for the sake of one over an entire cabin of guests and employees,” the flight attendant wrote.

— An immunocompromised passenger was furious at the lack of enforcement as another customer snacked incessantly on chocolate. The concerned passenger then removed his mask to complain to the flight attendant.

— A passenger claimed discrimination, arguing he was singled out for enforcement because of his tattoos. “He said ‘I am complying, #%$^!’ His nostrils were clearly visible,” the flight attendant wrote.

— A pilot flouted the mask requirement with what appeared to be a passive-aggressive display, donning a flimsy, see-through veil described as useless for containing airborne particles.

— Flight attendants made an exception and allowed a distraught mother, whose daughter may have had a disability and screamed about the mask requirement, to remain on the plane. They tried cookies, which didn’t help, then moved the family to seats three rows from other passengers, who were supportive.

— A customer, after earlier warnings, stuck his mask-free head in the aisle during the safety demonstration, “making a total mockery out of me,” a flight attendant wrote. He repeated his taunt when the plane was fourth in line for takeoff. The captain turned around, and the man was taken off the plane.

The obstinacy cuts against basic health precautions. Experts in cabin air say masks are critical tools for safety. Cabin air is run through powerful filters, mixed with outside air and recirculated. But it takes several minutes for all air to be vented out of the cabin, giving the coronavirus and other viruses the opportunity to spread.

A Harvard study funded by the aviation industry said flying can be done with a relatively low risk of coronavirus infection if precautions are followed. It said masks are “perhaps the most essential layer” among measures to reduce transmission.

The study said removing masks to eat should be kept to an “absolute minimum,” and straws should be used when feasible. “When one passenger briefly removes a mask to eat or drink, other passengers in close proximity should keep their masks on,” researchers said.

Trump and some of his advisers, meanwhile, have stoked divisions over masks.

The president mocked Biden’s frequent mask use, presided over White House events that flouted mask guidelines and relied on a former pandemic adviser who wrongly argued masks were ineffective. The White House also blocked a nationwide order, drafted by the CDC, that would have required masks on all forms of public transportation.

“Masks have been made a political issue from the start of the pandemic, and people don’t believe they need to wear them,” said Garland, whose union represents about 50,000 flight attendants.

“We do not have a president who tells people to wear a mask, and the federal government, not just in aviation but across the board, has declined to mandate it in any way, shape or form,” she added, saying her members are eager to see a Biden administration set a different tone.

An FAA spokesman declined to answer questions about the risks involved with passengers refusing to wear masks.

After inquiries from The Post about enforcement, the agency distributed a news release touting its role in pursuing civil penalties in two assault cases but reiterated that “the failure to wear a face covering is not itself a federal violation.”

The cases show how mask disputes can escalate.

On an Allegiant Air flight in August, a passenger hit a flight attendant, yelled obscenities at him and grabbed his phone as he described a mask-related dispute to the captain, according to the FAA. The agency said it is pursuing a $15,000 civil penalty for assault and interfering with a flight attendant.

Allegiant declined to say whether anyone was arrested or charged.

On a SkyWest Airlines flight to Chicago in August, a passenger took off a mask, “continually bothered” fellow customers and “at one point, grabbed a flight attendant’s buttock as she walked by the passenger’s row of seats,” according to the FAA, which is seeking a $7,500 penalty.

Beyond addressing such extreme cases, some outside experts say federal and corporate leaders have fallen short.

“Both industry and government have failed the people on the front line who need to administer these rules,” said Baruch Fischhoff, a psychologist and professor at Carnegie Mellon University who researches decision-making.

Politics often has driven responses to the pandemic, while critical public health communication on things like masks has not been tested to make sure it hits the right notes or is convincing, Fischhoff said. “Neither have fulfilled that responsibility for clear, consistent, tested communications,” he said.

Fischhoff said that with 330 million people in the United States, it’s not surprising the safety reports received by NASA reveal examples of poor behavior.

“Part of the reason they stand out is, I think, the vast majority of people are polite and civil to one another,” Fischhoff said. Still, the reports probably represent a dramatic undercount because it takes time and initiative for busy employees to file them.

“If you see 100, there are probably 1,000 or 10,000. This is a widespread enough phenomenon that it needs to be taken seriously,” he said. “You have to give credit to people who lodge just complaints and recognize they’re just a fraction of the people who are observing things that threaten our health and our economy.”