There are few things more frightening than experiencing a medical crisis at 36,000 feet.
Imagine being trapped in a tin can, high above the Earth, the nearest hospital hundreds or thousands of kilometres away.
You are dependent on the first-aid skills of a flight attendant or, if you're lucky, a physician or nurse who happens to be on the plane.
It is a fear that people with severe allergies know all too well - and doubly so because many airlines stubbornly insist on selling and serving foods that can trigger the most severe allergic reactions.
In its current edition, the Canadian magazine Allergic Living has highlighted this issue superbly in a cover story titled Plane Truths.
The magazine has also launched a "reduce the risk" campaign to put pressure on big airlines such as Air Canada and WestJet to make the skies safer for the growing legions of children and adults with severe allergies.
"Flying is a fundamental part of modern life, and the allergic have a right to do it safely - like everyone else," says Gwen Smith, editor of Allergic Living.
After all, what goes on a plane is a microcosm of the challenges of the real world for allergy sufferers.
This is not a group of nutty radicals asking for the world, but forced-by-circumstances activists looking to protect themselves and their children from real danger.
Essentially, the write-in campaign is asking the airlines to develop clear, consistent and articulated policies on allergies to minimize the risk of in-flight reactions.
"We're not asking for the allergy police. But there's a snack-nut culture on the plane that needs to change," Ms. Smith said.
In fact, the only place where people are exposed to more food allergens is in baseball stadiums.
No one is suggesting that the world - or every airplane in the world - can be made nut-free or allergen-free.
But the current attitude of airlines, which can be summed up as "hey, it's not our problem," is simply not acceptable.
More frustrating still - and more dangerous for allergy sufferers - is that policies are inconsistent.
Anaphylaxis is not to be dismissed casually: It is a severe, life-threatening systemic allergic reaction triggered by exposure to one or more antigens, including foods, insect stings, drugs or latex products. Up to 8 per cent of children have food allergies, and allergies to peanuts and tree nuts among children have doubled in the past five years.
There are about one million Canadians and 11 million Americans with severe allergies, and airlines that ignore this reality are toying with disaster.
Many airlines, to their credit, have stopped serving peanuts after research showed that peanut dust was readily circulated by airplane ventilation systems and that peanut oils could be found on many surfaces.
But airlines are a long way from being nut-free.
Snacks that are distributed now include cashews and other nuts, and sesame concoctions - highly allergenic foods, particularly for children.
Airlines have cut back drastically on the meals they serve, but paradoxically this may have increased the risk of exposure as passengers bring all kinds of foods on board, from sunflower seeds to pad Thai.
A new study showed that about one in 10 people with allergies suffer a reaction while on a plane, a frighteningly high number.
The folks at Allergic Living are not suggesting Draconian measures such as banning potential allergens. Rather, they are calling for more education and better communication by airlines.
A simple announcement by flight attendants that some people are severely allergic to nuts and a request to refrain from eating them on board could go a long way.
And surely doing away with the distribution of salty snacks entirely - or, better still, offering travellers a bit of fresh fruit instead - would not cause airlines any great hardship.
