Francesca Hogi, 40, had settled into her aisle seat for the flight from New York to London when the man assigned to the adjoining window seat arrived and refused to sit down. He said his religion prevented him from sitting beside a woman who was not his wife. Irritated but eager to get underway, she eventually agreed to move.

Laura Heywood, 42, had a similar experience while traveling from San Diego to London via New York. She was in a middle seat — her husband had the aisle — when the man with the window seat in the same row asked if the couple would switch positions. Heywood, offended by the notion that her sex made her an unacceptable seatmate, refused.

"I wasn’t rude, but I found the reason to be sexist, so I was direct," she said.

A growing number of airline passengers, particularly on trips between the United States and Israel, are now sharing stories of conflicts between ultra-Orthodox Jewish men trying to follow their faith and women just hoping to sit down. Several flights from New York to Israel over the last year have been delayed or disrupted over the issue, and with social media spreading outrage and debate, the disputes have spawned a protest initiative, an online petition and a spoof safety video from a Jewish magazine suggesting a full-body safety vest ("Yes, it’s kosher!") to protect ultra-Orthodox men from women seated next to them on airplanes.

Some passengers say they have found the seat-change requests simply surprising or confusing. But in many cases, the issue has exposed and amplified tensions between different strains of Judaism.

Jeremy Newberger, a 41-year-old documentary filmmaker who witnessed an episode on a Delta flight from New York to Israel, was among several Jewish passengers who were offended.

"I grew up Conservative, and I’m sympathetic to Orthodox Jews," he said. "But this Hasid came on, looking very uncomfortable, and wouldn’t even talk to the woman, and there was 5 to 8 minutes of ‘What’s going to happen?’ before the woman acquiesced and said, ‘I’ll move.’ It felt like he was being a yutz."

Representatives of the ultra-Orthodox insist that the behavior is anomalous and rare. "I think that the phenomenon is nowhere near as prevalent as some media reports have made it seem," said Rabbi Avi Shafran, director of public affairs at Agudath Israel of America, which represents the ultra-Orthodox community.

Shafran noted that despite religious laws that prohibit physical contact between Jewish men and women who are not their wives, many ultra-Orthodox men follow the guidance of an eminent Orthodox scholar, Rabbi Moshe Feinstein, who counseled that it was acceptable for a Jewish man to sit next to a woman on a subway or bus so long as there was no intention to seek sexual pleasure from any incidental contact.

"The haredi men I know," Shafran said, using the Hebrew word for the ultra-Orthodox, "have no objection to sitting next to a woman on any flight."

But multiple travelers, scholars and the airlines themselves say the phenomenon is real. The number of episodes appears to be increasing as ultra-Orthodox communities grow in number and confidence, but also as other passengers, for reasons of comfort as well as politics, push back.

"It’s very common," said Rabbi Yehudah Mirsky, an associate professor of Judaic studies at Brandeis University. "Multiculturalism creates a moral language where a group can say, ‘You have to respect my values.’"

Anat Hoffman, the executive director of the Israel Religious Action Center, which has started a campaign urging women not to give up their seats, said, "I have 100 stories."

And Rabbi Ysoscher Katz, a Modern Orthodox Talmud scholar who grew up in the ultra-Orthodox Satmar sect, said, "When I was still part of that community, and on the more conservative side, I would make every effort I could not to sit next to a woman on the plane, because of a fear that you might touch a woman by accident."

Airlines, and flight attendants, are often caught in the middle. Morgan Durrant, a Delta Air Lines spokesman, acknowledged the phenomenon, saying: "This is a dynamic of some customers who utilize our service. We’re aware of it, and we do what we can to get ahead of it prior to boarding."

Other airlines had little to say about the situation, other than to agree that a variety of passengers make a variety of requests when traveling, and that carriers try to accommodate them.

It is not an entirely new issue; some ultra-Orthodox travelers have tried to avoid mixed-sex seating for years. But now the ultra-Orthodox Jewish population is growing rapidly because of high birthrates. Ultra-Orthodox men and their families now make up a larger share of airline travelers to Israel and other locations, and they are exerting their economic influence more often, making their views more widely known in response to what they see as the sexualization of society.

The issues on airplanes echo controversies over efforts to separate men and women on buses and streets, as well as to remove women from some news photographs.

"The ultra-Orthodox have increasingly seen gender separation as a kind of litmus test of Orthodoxy — it wasn’t always that way, but it has become that way," said Samuel Heilman, a professor of sociology at Queens College. "There is an ongoing culture war between these people and the rest of the modern world, and because the modern world has increasingly sought to become gender neutral, that has added to the desire to say, ‘We’re not like that.’"

Some passengers are sympathetic. Hamilton Morris, a 27-year-old journalist from Brooklyn, said he agreed to give up his seat on a US Airways flight from Los Angeles to Newark via Chicago because it seemed like the considerate thing to do.

"There was a Hasidic Jew sitting across the aisle, between two women, and a stewardess approached me and quietly asked if I would be willing to exchange seats because the Hasidic Jew was uncomfortable sitting between two women," he said. "I was fine with that. Everyone was trying to be accommodating because on airplanes everyone is anxious about offending anyone for religious reasons."

And yet Heywood, a paralegal from Chula Vista, Calif., said she declined to give up her seat for reasons of both politics and seat preference — her husband finds flying less stressful in aisle seats. "I wasn’t going to put his comfort for no good reason above my husband’s," she said.

Other passengers, like Andrew Roffe, a 31-year-old writer based in Los Angeles, said he and a friend wound up debating the ethics of the situation after Roffe described his experience on a United Airlines flight to Chicago. When they started to board, he said, an ultra-Orthodox man stood in the aisle, refusing to move and delaying the departure for 15 to 20 minutes until another passenger volunteered to switch seats.

"My buddy who is Orthodox was saying this is a traditional thing — he doesn’t want to be tempted when his wife wasn’t there. And I said, ‘Are you kidding?’ This was just some woman flying to work or home and minding her own business."

Michael Paulson, New York Times

© 2015 The New York Times Company