But some airline pilots and safety experts have raised concerns that such policies leave children vulnerable to severe injury in an onboard emergency. Millions of children fly unaccompanied every year as air travel becomes ever more frequent, with many families, separated by divorce or jobs in far-flung places, living apart.

And despite a number of lawsuits arising from the seating question — mostly in the United States — the industry has so far not adopted consistent policies to reconcile the competing fears.

In one case, two children on a domestic Air France flight in February were unable to reach the oxygen masks that deployed when the plane abruptly lost cabin pressure. The sobbing children — a boy and a girl, ages 8 and 10 years old — were seated in separate window seats of the Embraer ERJ-145, with the aisle seats empty. A flight attendant eventually helped them with their masks, and the plane landed safely in Paris 30 minutes later.

Air France confirmed the details of the episode, and that the airline now systematically seats unaccompanied children ages 5 to 12 in a row by themselves. Brigitte Barrand, a spokeswoman, said Air France had adopted this seating policy about a year ago after a series of complaints of ‘inappropriate touching’ of children on some of its long flights.

She declined to disclose how many incidents there were, but said it involved a ‘very, very small number’ of the roughly 4,00,000 unaccompanied minors the airline carries each year.

“Increasingly, many families are living far apart from one another, and parents are trusting us to take care of their little ones,” Barrand said. “Their security and tranquillity absolutely has to come first.”

Unnecessary risk

But last month, pilots’ unions at Air France formally voiced concern, arguing that the policy placed such children at unnecessary risk in cases where they might need extra assistance.

“It is absurd to leave these children seated by themselves,” said Louis Jobard, president of the Air France branch of the Syndicat National des Pilotes de Ligne union. “We think that the possibility that a child could be the victim of sexual harassment on board is much, much smaller than the risk that they could be hurt, for example, while not properly restrained” in an emergency.

Other international airlines have made similar changes. British Airways, Qantas and Air New Zealand have recently modified longstanding policies that had required children travelling alone to be seated next to an adult female, following a spate of lawsuits and negative publicity from men who said they had been victims of sexual discrimination when asked to move.

Many parents said they were unaware of such seating changes, which airlines do not typically spell out on their websites or when the child’s ticket is bought. “I had never anticipated that children would be out of sight, several rows away” from flight attendants, said Caroline Bourke, 45, whose 11-year-old son regularly flies alone on Air France. “But also I never had the idea that something sexual could happen,” she said. “I wouldn’t like an unknown adult to be placed beside my child.”

There is no industrywide policy covering unaccompanied minors; not all airlines will accept them. Those that do generally require the child to be at least 4 or 5 years old. For children up to the age of 11 or 12, parents are required to pay for an extra service, which includes escorting the child on and off the plane and through any transfers, and handing the child over to a designated adult at the end of the journey. Teenagers often travel on their own.

As for the risks of either sexual abuse or physical injury onboard, they are slight but difficult to measure. Over the past decade, fewer than five passengers a year have suffered serious injury from turbulence on a United States commercial flight, according to the Federal Aviation Administration. Regulators in the United States and Europe said they did not publish statistics on cabin depressurisations.

Unclear data

The industry does not track the number of unaccompanied children who fly every year. Analysts and airline executives put the number at less than one per cent of the 2.4 billion people who board a commercial aircraft each year, which could still be around 20 million.
National law enforcement agencies do not break out statistics on sexual abuse aboard aircraft. Although several lawsuits have been filed, it is unclear whether anyone has ever been convicted for such a crime.

Many airlines, which typically charge an extra $50 to $150 for unaccompanied minors, are reluctant to discuss the issue. And while most of the sexual abuse litigation is taking place in the United States, none of the major American carriers — even some that have been sued — said they were taking any steps to modify their seating policies.

All of this leaves parents struggling to weigh the relative risks to their children when they put them on a plane alone. “I’ve considered the whole inappropriate behaviour thing, although it isn’t a forefront-of-my-mind type of concern,” said Kimberley Jardine, 40, a freelance writer in Austin, Texas, whose eight-year-old son flies to Seattle every summer to visit relatives.

“A child needs to be near an adult in case of an emergency, for the mental support,” Jardine said. But she said she had already told her son to plan on fending for himself. “I imagine many adults would simply shove a child out of the way if they are panicked.”