Dana T. had never felt more excited about her life. In April, she’d landed what she calls her “dream job,” working in sales at a global travel company. Like every other employee, she would need to attend training at the company’s headquarters in Cologne, Germany. So on May 7 she arrived at the Newark, New Jersey, airport for her first-ever international flight. “I felt like the luckiest person in the world,” she told me.

When she found her seat on United Airlines Flight 960 to Frankfurt, Germany, she immediately took note of the man beside her, in the middle seat. “He was shaking his legs,” she says, “I thought from nervousness.” She hoped her neighbor’s restlessness wouldn’t keep her awake. “I thought, ‘I don’t want to be jetlagged.’ I’d heard about that but never experienced it.” She drank two glasses of red wine with her meal and put on the longest movie she could find, The Revenant, to help herself drift off.

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The next thing Dana remembers is groggily registering the man next to her, who had covered his lap with a blanket. He was gesturing toward his crotch and saying, “Lay on my lap.” “Since I was half asleep and clearly did not want to be disturbed, I just gave him a weird look and said, ‘Um no,’ ” Dana wrote in an email to me. (I am withholding her full last name to protect her privacy.) “I just thought the guy was weird.” Later, the man woke her again; she glared at him and he seemed to back off. At this point, Dana recalls, the plane was somewhere over the Atlantic Ocean, the cabin lights were off, and everyone around them seemed to be asleep. She wasn’t sure of the hour, but she was exhausted and quickly drifted off again.

Then Dana jolted awake to a sharp pain. The man had her left breast in his hand and was pinching her nipple over her shirt. When she bolted up, she says, he gasped, “Oh sorry! Sorry!” She jumped from her seat and sprinted down the darkened aisle.

“I think this man is touching me,” Dana says she told the first cluster of flight attendants she found: two men, one of whom was a German from United’s partner carrier Lufthansa, and one woman. (Update, Dec. 13, 2016: Lufthansa has since reached out to say that there were no Lufthansa attendants on the United flight.) The female attendant responded, “You think he is?” “No, no, he is, he is,” Dana said. But in her mind, Dana wondered, Why are you asking me like that?

Dana says the female flight attendant told her to sit back down, but she refused; she also advised the crew to move the young woman on the other side of the perpetrator to another seat—she looked to Dana like she might be in her late teens.

The German flight attendant disappeared down the aisle and reappeared a few minutes later to announce he had “yelled at him.” Dana says the flight attendant told her that the man had at first pretended to be asleep and then begged, “Please don’t arrest me. It was an accident.” “When I heard about what the guy said, my heart just dropped,” Dana says. She thought, “That really was happening … This guy just admitted it.” That’s when she started to cry, she says.

The crew found Dana a new seat in business class, where she sat shaking while people snored around her. She says she told her story to every flight attendant who walked by, and they responded by “throwing things at me—free stuff, trying to make me happy. I feel like they were like, ‘Oh, what an asshole! Would you like more wine?’ ” One German flight attendant stopped by to explain that “people, they move around in their sleep sometimes” and that “Indian men do this all the time.” (The alleged assailant appeared to be of South Asian descent.) After Dana had calmed down, she says she walked to the front of the first class section to ask members of the flight crew what they planned to do about the man. According to her, “They just stared straight ahead and ignored me.”

There was one American flight attendant who seemed sympathetic, Dana says. She told Dana that the crew had put “a note on [the man’s] profile.” (None of the airline industry sources I spoke to for this story had heard of airlines taking notes on passengers or could tell me what such a “profile” might be.) This attendant also snuck down the aisle to snap a photo of the man on her cellphone. “She seemed to care, so I asked her, ‘What would you do?’ ” Dana says. The woman told her to report the incident to the Lufthansa agent at the gate when the flight landed.

But when the doors opened, Dana had the feeling something was wrong. “I stood there and watched as they let everyone off the plane,” she wrote to me. “They let the man off the plane.” When she reached the Lufthansa agent, he “was furious to hear from me and asked me why it wasn’t reported before the plane landed, to which I replied, ‘It was.’ ” But apparently the crew had not radioed the information to the ground. Dana says the agent told her that, because the police had not been called to meet the plane, and the man and any potential witnesses had already left, there was probably nothing to be done. Over the coming hours, days, and weeks, she would hear the same thing from airport security in Frankfurt; the German police in Cologne; and, when she returned home, the FBI in New Jersey.

Dana’s last glimpse of her flight’s crew was of the sympathetic American attendant. “When I was sitting there talking to the cops in the ground control … she ran over to them and knocked on the window and said, ‘I have a picture,’ as if she thought this was going to help my case.” Dana says. “She really wanted to help, I think. But she unfortunately was not trained on how.”

* * *

How often do fliers—especially women traveling alone—have experiences like Dana’s on airplanes? And how do flight crews and airlines respond? These questions are surprisingly difficult to answer, but I spent two months trying, sending out requests for information that bounced between three different federal agencies and countless airport representatives.

First, the numbers. An FBI spokeswoman told me that the agency had 40 open cases involving sexual assaults on aircraft in 2015 and 37 cases so far this year. But the FBI doesn’t currently track sexual assaults on planes in its Uniform Crime Report, its official, nationwide effort to collect crime data from all levels of law enforcement. Thus it’s impossible to say how many reports made to airport security officers and local police departments aren’t reaching the FBI’s stats. After it was revealed that at least four sexual assaults had occurred on aircraft headed for Washington-metro-area Reagan National and Dulles airports in 2014, Congresswoman Eleanor Holmes Norton tried unsuccessfully to pass a bill that would have compelled the Federal Aviation Administration to keep statistics on the problem. At this point, as NBC has reported, “no federal agency is maintaining data” on this particular crime.

There’s also the reality that most sexual assault victims don’t report, so even if the government tried to keep figures, it would be nearly impossible to get an accurate count. None of the U.S. airlines contacted for this story—United, American, JetBlue, Southwest, Delta, Frontier, Spirit, and Alaska—would share data about sexual assaults on their planes. United also declined to comment on Dana’s case. Lufthansa confirmed that Dana had reported an incident to United but could not comment further on her case.

The stories that have made it to the press, however, suggest that planes are more treacherous places for female travelers than most people realize. A casual search yields many examples: In 2014, a Catholic priest was accused of touching a woman’s “breast, inner thigh, and groin” on an overnight flight from Philadelphia to Los Angeles; he later told authorities that he enjoyed “cozy flights” with women. A Hawaiian man who attempted to rape a woman in an airplane lavatory en route to Japan was stopped only when other passengers ripped the bathroom door off its hinges. In 2015, a New Jersey woman flying from Dubai to JFK popped a Xanax to help her sleep and woke to find that “her vaginal area was sore” and “that her underwear had been shifted and that lotion was in her vaginal area and on her underwear,” according to a criminal complaint. The Staten Island man seated next to her had stolen a bottle of Nivea lotion from her bag and rubbed it on her body and between her legs.

This June, the Washington Post reported the story of a 13-year-old girl who said she was sexually assaulted while flying alone from Dallas to Portland, Oregon. Her lawyer, Brent Goodfellow, told me that after the case made headlines, calls and emails from other women who’d been assaulted on planes poured into his office. When I asked how many he’d received, he thought for a minute. “Fifty,” he estimated.

These incidents tend to follow a pattern, says Dana LaRue Park, a blogger who told me she’s heard from at least 10 victims since 2011, when she wrote about being sexually assaulted on a flight from Los Angeles to Chicago. Like her, the people who’ve contacted her were all “women traveling alone, on overnight flights.” Usually they’d taken some sort of sleep aid; often they’d covered themselves with blankets that concealed the assailant’s roving hands, or the assailant had covered them for that purpose, as LaRue Park says her assailant did with his jacket. Middle or window seats can make a victim “feel trapped”; LaRue Park, for example, says she didn’t report to the flight crew while the plane was in the air because she would have had to push past the man to reach the aisle.

Of course, the things that make female fliers targets—taking a red-eye; sleeping on said red-eye like everyone else—are basic elements of travel that shouldn’t be off-limits to half the population. Airlines, however, have few policies in place that suggest they feel responsible for managing the risks particular to women. “I don’t believe this is being addressed, and I don’t believe it’s being addressed across the aviation industry,” Sara Nelson, president of the Association of Flight Attendants, told me. “We have general protocols for assault on the airplane,” she says, but “the training and protocols are lacking” when it comes to sexual assault in particular.

If the crew on Dana’s flight didn’t seem able to deal sensitively with a victim or distinguish the line between boorishness and sexual assault, it was probably at least in part because they hadn’t been trained to do so. United wouldn’t comment on its training and safety protocols. A Lufthansa representative told me only that “dealing with aggressive behavior of any kind is part of our Human Factors Training,” required for all crew members, and that “the Lufthansa Group does not tolerate any sort of aggressive behavior.” Heather Poole, a flight attendant who has worked in the industry for 20 years—and written about her own experiences being groped by passengers—told me she has never received, or heard of, training that specifically mentioned sexual assault.

For the authorities to have met Dana’s plane and arrested her alleged assailant, the flight crew would have had to go to the pilots—the only people with the authority to radio the ground—who would in turn have had to decide that the incident merited a report. In extreme situations, if passengers or crew are in immediate danger, pilots can divert their flight, radioing down to the nearest airport for permission to land. But communication between cabin crew and captain isn’t always crystal clear, according to Poole. “The captain makes the call,” Poole says, and “there’s a big divider between us and them.”

Local law enforcement is an additional variable, especially if the plane is landing in a country, such as Germany, where authorities take a notoriously blasé stance on sexual assault. According to Dana, when she went to the police station in Cologne, “They said, ‘What happened to you here is considered just rude. Just let it go.’ ”

When she got home, Dana went to the FBI. A spokeswoman for the violent crimes unit within the FBI’s Criminal Investigative Division, which handles sexual assaults on planes, told me that the FBI and foreign law enforcement will usually collaborate on investigations, but the bureau generally maintains jurisdiction over crimes that occur on U.S. airlines. (The FBI also has jurisdiction over crimes that occur in U.S. airspace.) Dana told me that the FBI investigators she’s spoken to, though they’ve been kind, have seemed intent on preparing her for disappointment. (It is against the FBI’s policy to comment on or confirm the existence of any specific investigation.) If the FBI isn’t there to meet the plane when it lands, investigators face setbacks that can “hinder the collection of evidence and statements,” as the FBI spokeswoman wrote to me. Even though the bureau can generally subpoena the name of the alleged perpetrator from the airline, possible witnesses have dispersed, and the victim’s own memory may no longer be as clear.

LaRue Park has observed “some form of urgency that happens if it’s reported in the moment.” She would advise victims to “create the biggest scene possible in the middle of the act, so someone will look and you’ll have witnesses.” But, she says, “It just seems that cases, even without a witness, are taken a lot more seriously” if the crew calls from the air.

* * *

In the fundamental decision of whether to call down, as in all aspects of their response to sexual assault onboard, crews appear to be given little guidance—from the airlines or from the federal government. When I first contacted the FAA, spokesman Jim Peters referred me to the Transportation Security Administration. The TSA informed me that it deals with “counterterrorism, not law enforcement issues aboard aircraft,” and sent me back to the FAA. This time, Peters emailed me the pertinent section of the Federal Aviation Regulations—Part 121.421.ii—which stipulates simply that flight attendants must be trained in “Passenger handling, including the procedures to be followed in the case of deranged persons or other persons whose conduct might jeopardize safety.”

“Each carrier decides how to implement the regulation, the FAA does not tell them how to do that,” Peters wrote, adding: “Generally, flight crews have wide discretion about whether to call law enforcement to meet an aircraft and the FAA does not have a requirement for flight crews to notify authorities when a passenger alleges a sexual assault during flight.”

Most of the airlines I contacted were not enormously forthcoming about their approaches to implementing FAA regulation 121.421.ii. A spokesman for American Airlines wrote to me in an email, “In all cases of misconduct between two passengers, we will immediately separate them, and request law enforcement meet the aircraft. … Out of an abundance of caution, our employees are trained to report any activity that is out of the ordinary to law enforcement.” A spokeswoman for Southwest wrote that “our Crews are trained on self-defense tactics for various types of assaults. Depending on the situation, our protocols do include separating individuals and providing the proper notifications.” After I emailed United to ask what training crews received about sexual assault and what protocols for response the airline had in place, a spokesman referred me to the TSA. JetBlue, Delta, Spirit, Frontier, and Alaska failed to respond to requests for comment about crew training and in-flight protocols around sexual assault.

In practice, it appears that crews’ responses vary widely. Goodfellow, the lawyer for the 13-year-old victim, connected me with an adult victim whose case he’s also representing. I’ll call his client Lorrie to protect her privacy; she’s still afraid of her alleged assailant. Lorrie was flying from London to Dallas on American Airlines in September when she was, she says, “stalked and harassed repeatedly by a deranged individual.” She noticed from the moment the man sat down next to her that he was “mumbling to himself and kind of clenching his fists angrily,” she says, and shortly after takeoff, he began leaning his body weight into her, pinning her against the window, and “would place his face less than an inch from mine and stare, and he had his hand on his crotch,” she says. Lorrie managed to push past him and tell the head flight attendant, who moved the man to another seat. But minutes later, Lorrie says, he walked back up the aisle and stood over her, “clenching his fists and hitting the [tray] table” while she sobbed in panic.

From here, Lorrie alleges that the American crew grossly mishandled the situation. For the rest of the roughly 10-hour flight, they kept moving the man, she says, and the man kept coming back. After his third reappearance, the crew threatened to restrain him with handcuffs—but they never actually did so, she says, and it wasn’t clear to Lorrie that they knew how. After what Lorrie believes was the man’s eighth return, the head flight attendant came and sat with her; the next two or three times, he was there “to meet him and escort him back.” After that, one of the two pilots took the flight attendant’s place guarding Lorrie; about an hour later, he and the other pilot swapped. “I couldn’t believe they brought a pilot out,” Lorrie says. “That seemed like one of the biggest safety risks.”

From the pilots, Lorrie learned that the crew had strongly considered diverting the plane. “I learned about all the activity between them and the other countries, all the places where they had clearance to land,” she told me. “They even said they should have [diverted]. They said it was very expensive and everyone on the flight would have been extremely inconvenienced.”

American Airlines spokesman Ross Feinstein told me that it is “up to the discretion of the pilot of an aircraft whether they would divert or not,” adding that many factors have to align to make a diversion possible. If the plane is “over weight”—heavy with fuel that would have burned off over the course of a longer voyage—the pilot may need to circle for hours before it’s light enough to safely land, he said. What’s more, in an international diversion, the new destination must have customs officers available to process the passengers.

Though Lorrie says the police escorted the man off on landing, they decided, for reasons unclear to her, that they didn’t have enough information to hold him. American confirmed that authorities met Lorrie’s plane but otherwise declined to comment on her case. She told me she continues to live in fear of running into the man in Dallas, her home. She doesn’t know his name.

Diversions can cost anywhere from a few thousand dollars to more than $100,000—but some crews decide the price is worth paying, especially when an assailant doesn’t seem easily cowed. An Alaska Airlines flight from Portland to Anchorage landed in Seattle in June after a 23-year-old man drunkenly groped the 16-year-old girl seated next to him, continuing after she pushed him away and forcing his tongue into her mouth. Even when crews make the calculation to stay on course, they can do more than simply radio the ground and separate accuser and accused.

“Our job is to keep the situation from escalating,” Poole, the flight attendant, wrote to me in an email. “We aren’t going to run up and down the aisle yelling ‘molester.’ ” But crews need to balance the importance of maintaining calm onboard against the need to gather information and, of course, to keep the assailant under control. Though Poole has never dealt with the sexual assault of a passenger, she told me she would discreetly look for witnesses. If the flight was full, she would also have to ask herself: “Who can I seat next to the assaulter? Who can handle it?”

It appears that the crews on Dana’s and Lorrie’s flights never informed the other passengers of the incident or asked them if they’d seen anything. Both women told me that the crews left the lights off and the seatbelt signs dimmed as if everything was routine. But some crews make different choices. The FBI’s report on the Catholic priest who assaulted a woman en route to Los Angeles noted that the crew “reseated [him] in the front of the plane in a seat between two male passengers”—presumably so that both the flight attendants and his new seatmates could keep an eye on him. After the 13-year-old was allegedly assaulted on her way to Portland, her lawyer says, the crew identified a passenger who said he’d seen the man seated next to her drinking heavily in an airport bar; they moved the possible witness to the front of the plane along with the girl. They also turned on the fasten-seatbelt sign for the duration of the flight, possibly, the lawyer thinks, to preserve any evidence for the authorities.

A person who gets punched in the face on an airplane can expect that the flight attendants have been trained to respond, according to the AFA’s Nelson—but, at least for the moment, a victim of sexual assault simply can’t predict how the crew will react. “We’d like to see standard reporting procedures across the industry,” Nelson told me. “I think in most cases and with most airlines, the authorities are meeting the airplane. But when you don’t have consistent procedures, it’s possible those things aren’t happening.” She’d like to see the government and the airlines set rules to cover the basic questions that crews inevitably have in the moment: “Are you trading seats? Are you getting a passenger to volunteer to sit next to the person who’s been a problem? Are you detaining them?”

As long as crews have to decide those things in the air, and with insufficient training to guide them, some will get it wrong. That has left Dana, for one, feeling nervous about the fact that she’ll have to fly to her company’s headquarters in Germany again. The FBI is still investigating her case, but what she really wants to know, she says, is: “Basically, is it safe to fly with United?” She commented about her experience on the airline’s Facebook page and immediately got a message from its communications team, but the corporate senior manager to whom she was referred has told her “that it is being handled by the FBI and there is nothing else that can be done,” she says.

At this point, after months of calls to the airline and the FBI, and of telling her “story story story, over and over again,” she says, close friends are advising her to let go and move on for sanity’s sake. “The more I try to do something about it, the worse it gets for me,” she says. She’s been struggling with anxiety. “I felt like they were basically saying, ‘What do you want us to do? Your body is going to be touched. Your body is not your own,’ ” she says. “I went through my whole life thinking if something ever happened to me, of course there would be recourse. Now that I realize there isn’t, it’s a scarier world.”

Planes give many people an odd sense of safety: Far above our planet’s atmosphere and its everyday norms, it feels ordinary to sleep squeezed between total strangers. Dana will probably never experience air travel that way again. She remembers the sympathetic flight attendant saying to her, “Don’t worry, honey, we have him on a plane. He can’t go anywhere.” For a few hours, that was true. “But they let him go.”