Superstitions are not something people tend to boast about. One traveller I know carries a good luck charm in the shape of a small golden pig, which she holds tightly during take-off and landing. There must be thousands like her. Others will demand to sit in the back of the plane, something which has not been shown to improve your chances in the event of a crash - and then stubbornly study the carpet pattern or read the in-flight magazine as the safety drill is demonstrated by the cabin crew.
Even those coolly logical pilots are prone to the occasional irrational thought. The aviation writer Steven Barlay recalls a pilot he knew who added a ritual to his inspection of the aircraft before take-off. "There was one particular spot he always had to touch," says Barlay. "I think it was on the top left-hand side of the opening. He was not afraid of flying; he was not worried about it at all. But he would do it every time."
And could it be that Boeing's love for the number seven has anything to do with its traditional status as a lucky number? Would generations of Americans have been just as happy flying in a Boeing 666?
Manufacturers and airlines usually take no position on such issues. None admits to superstition among their staff. Of those we questioned, Qantas was in the vanguard of the rational flight. Not only did the company insist that none of its crew or pilots considered themselves superstitious, the airline also assured us that no member of staff had heard of a passenger being superstitious before or during a flight. No Qantas passenger has, apparently, ever been wary of the number 13 in flight times, flight numbers or seat row numbers.
British Airways and Air France were happier to acknowledge superstition - among passengers, at least. On the question of whether there were Air France passengers who feared the number 13, a spokeswoman said: "Oh, I'm sure there are lots of people who'd prefer to take another flight rather than sit in seat 13."
To deal with this problem, BA has aircraft on which the row numbers jump from 12 to 14. The airline also reports cases of passengers asking for boarding cards to be changed if they find the number 13 on them, and of bookings dipping on Friday the 13th. British Midland also avoids seat rows numbered 13: "I don't think they were ever introduced," said a spokeswoman, unafraid to acknowledge the X Files factor. Later the conversation turned naturally to the spirit world. "There are reports of the `Teesside ghost' up at Teesside airport," she said, chillingly. "It's actually at the hotel that the crew stay in; there have been incidents, apparently."
If any airport were to be haunted, it should be Heathrow. A ghost is occasionally mentioned, but no one seems to know who or what it is a ghost of. Travellers on the 13th should be aware that there are plenty of candidates. Highwaymen used to be strung up along the length of the nearby Bath Road. Violent highway robbery around what is now Heathrow Airport was once so common that there was a case in which an injured victim died because his doctor was waylaid by another highwayman while coming to treat him.
Then there is the dead village of Heathrow itself, complete with a Saxon temple, lying beneath the concrete of the airport runways. The site of Hounslow barracks is nearby, where a soldier called Private White was flogged to death, an event that led to the banning of flogging in the British army. Or perhaps the Heathrow ghost has something to do with the 60 travellers who were boiled in oil over the years at The Ostrich pub in Colnbrook village, three miles from present-day Heathrow. A landlord there during the 18th century had an excessively entrepreneurial outlook, and arranged a room in his inn so that wealthy tradesmen could be tipped from their beds while they slept, through a trapdoor and into a bubbling vat in the room below.
So modern-day passengers with feelings of impending doom should count their blessings. No longer do rapid descents through the airspace of Colnbrook tend to lead to disaster. But the fact remains that all airline passengers are travelling in a far odder way than those who stay on the ground. In 1910, a minister was telling the House of Commons: "We do not consider that aeroplanes will be of any possible use for war purposes." Ninety years on, our instincts still haven't got the measure of the activity.
According to Dr Alan Roscoe, a physician specialising in aviation, 80 per cent of regular fliers have some apprehension when stepping on to an aircraft, on whatever day of the year.
This is fertile ground for year-round superstition, which also tends to be nourished by the extraordinary nature of the statistics surrounding air travel. Suffice it to say that you are far safer in an aircraft than in a car (by a factor of 82, in the latest US research). In preparation for this Friday the 13th, Independent researchers trawled back through all the air accident reports of the Nineties. It turns out that the number of people who have died in air crashes on Fridays the 13th this decade is almost exactly the average for any other day of the year. Happy landings.