I can't think of any worse start to a day than waking up ready to catch a plane only to be told that Burger King had just caught fire at Heathrow Airport. To judge by the state of the road to Heathrow last Friday morning, I am not the only one.

Inevitably, the police issued their pleas for people not to travel to the airport. Inevitably, passengers were begged to call their airlines and to stay sensibly at home until conditions had eased. And inevitably, nobody took any notice.

Stay at home? And watch your winter holiday disappear because of an unfortunate incident in a burger bar? It may be that some people who are about to depart for faraway continents don't bother listening to the morning news at all. But even for those who knew Heathrow was on fire, unsurprisingly, the temptation to ignore advice and struggle through to their terminal was far too great.

Of the tens of thousands of passengers whose flights were cancelled, a remarkable number went to the desperate lengths of abandoning their cars to the mercy of thieves and tow-trucks and walking three miles to the terminal, lugging heavy suitcases on their backs. Only after seeing for themselves that their flights had really, truely, honestly been cancelled, could they resign themselves to the unimaginable and incredible truth.

And what a bitter truth that was. In this day and age there can be no more profoundly apocalyptic nightmare than having your flight cancelled. Throwing away your new Alfa Romeo somewhere in Middlesex and voluntarily joining a flood of planeless refugees seem relatively minor disasters by comparison.

Because tickets are printed in indelible red ink. A ticket can tell you months in advance exactly where you will be on a certain day in December at 9.05am. This is the modern world's equivalent to faith in God. To know that you will be sitting in, say, Burger King in Heathrow Terminal One at 8.15am in a month's time is as sure and comforting as the belief that one day you will check into that great terminal in the sky.

If safe departures have come to seem more certain than the afterlife, it is thanks to the impenetrably complex structure of air travel. The combined ranks of tour operators and airline officials and pilots and airport stewards and air traffic controllers will all conspire to ensure that I will take my seat at Burger King at 8.15am on a certain day in December.

They also ensure that I will board the plane at 9.05, that I will receive instruction in evacuation procedures, that the aircraft will taxi to the runway, that it will lurch forward without inducing panic in me or my fellow passengers, and that it will begin rumbling its way inexorably towards take-off.

No, there is nothing like missing a plane. The mere thought of a cancelled flight immediately taps in to our most horrible fears of locusts and primaeval chaos. If a plane can be cancelled today, the sun might as well not rise in the Maldives tomorrow and British Airways might as well change its name to Aeroflot.

And that comes on top of the practical complications: the relatives waiting in vain for your arrival in Malaga, the hotel rooms unclaimed, the time off work pointlessly arranged, the swimming costumes uselessly purchased. The outlook on life irredeemably and permanently damaged.

And all on a huge scale. The spiritual equilibria of 50,000 people, gone at a stroke. No wonder the road to Heathrow was littered with the detritus of people's lives on Friday.