Travelling will likely never be the same again. In the short term, thousands of people due to travel to North America this week have not been able to do so and many people have cancelled or postponed trips to Middle East countries. But already a feverish review of airport security around the world has led to anyone taking a holiday, or travelling on business, having to reschedule their timing.
The most obvious change is that passengers will have to leave for the airport earlier. Airlines are saying that an extra hour for checking in would be sensible - even for those heading to the Mediterranean and other short-haul destinations. Package tour companies Thomas Cook and Virgin Sun, for example, are advising customers to check in three hours before departure, rather than the usual two. Cook's charter airline JMC is suggesting long-haul passengers, who are normally asked to check in at least three hours before take off, allow an extra 30mins to an hour.
And passengers will need to cut the time they spend browsing in terminal shops or snacking before take off - for three reasons: first, it is certain that check-in staff will take more time scrutinising travel documents; second, their body and bag searches at X-ray machines and metal detection arches will become more painstaking, causing tailbacks at busy times; and third, the Department of Transport, Environment and the Regions has decreed that cabin bags should be searched again once travellers reach their departure gates.
When their holidays end, some package customers will be asked to catch transfer coaches from their hotels and apartments earlier, too.
A spokesman for the major tour operator, Thomson, said: "The security response to what has happened will be very different depending on the country, but we are trying to stagger arrivals at airports so that bottlenecks do not occur."
Frustratingly, however big the additional time buffer they build in, travellers may suffer more delays as take-off slots are missed while airline staff take longer to check aircraft cabins and track down missing passengers. Clearly the effects of heightened security will be especially marked in the US, where nerves at airports will now be set on edge by the slightest suspicion of another outrage. Travellers can expect much closer scrutiny when they switch between domestic flights.
But as William Gaillard, communications director of the International Air Transport Association, to which the world's major airlines belong, points out, the zealousness of security there will have to be balanced against the need to avoid massive disruption. "The problem is that in the US flying is like hopping on and off buses. There is no doubt that because, before this week, they hadn't had any successful hijackings for about 15 years, security had become a bit routine. But at the same time you can't make measures too cumbersome when you have six to seven million people flying around the country with sometimes minimum check-in times of only 20 minutes."
At Dallas-Forth Worth Airport, one of the world's biggest, the authorities have declared that all cutlery in the cafes and restaurants has to be plastic.
Cancellations
In the immediate aftermath of the attacks, travellers will have awkward decisions to make about whether to axe trips to the US or the Middle East. It was not just flights to the US and Canada that were grounded on Tuesday. Israeli airspace was also closed, disrupting the plans of those heading for the Red Sea resort of Eilat, for example.
All the major British tour companies told customers due to fly to the cities directly affected - New York, Washington and Boston - before midnight on Tuesday night that they could cancel their holidays or switch to an alternative or later holiday without penalty. Even though some flights have already started again, this still applies.
What happens after Wednesday? Holidaymakers may be disinclined to travel, not least because of a feeling that they would be impinging on private grief. But when it comes to allowing customers to cancel or postpone packages free of charge, tour operators usually rely on advice from the Foreign Office. Alan Flook, secretary general of the Federation of Tour Operators - which represents 12 leading groups - said: "It is standard practice that unless the FO says you shouldn't go somewhere, operators will not allow cancellation without imposing a financial charge."
However, Thomson, for one, was clearly sensitive to the unprecedented nature of the current crisis. "We will review the situation daily," said its spokeswoman.
There is uncertainty, too, for those who have booked holidays to other areas, such as Florida. Their trips were suspended for only 48 hours after the attacks. But those holidays remain contingent on reaction in the US to any further terrorism scares - or to the effects of any American retaliation. A spokesman for the Association of British Travel Agents said: "If everything is functioning again in Orlando and you said you didn't want to go, that would be seen as a cancellation and you might be charged a penalty. But if all the theme parks closed down I don't think the tour operator would see that as an acceptable position."
Insurance
Package customers who decide they no longer want to travel even when operators have resumed normal service may find they are not covered by insurance against any costs they incur. Reflecting the language of political leaders, the question was raised immediately after the attacks whether war exclusion clauses might apply. Some industry sources thought this unlikely, however.
Holidaymakers will need to check the fine print of their policies. The wording varies widely, said Richard Jones, a director of AON Suretravel, which acts as an insurance broker to travel firms, helping to arrange the policies sold by tour operators and high street agents. "Some policies specifically exclude terrorism, some don't. Some cover cancellation, curtailment of a holiday or delay - some don't. Some cite specific reasons why the traveller may cancel, such as illness, the death of a close relative or jury service." He fears insurance prices may rise. For further details see Jobs&Money.
Numbers travelling
Over the next few months, the probability that Americans in particular will be deterred from flying may force airlines to cut this winter's fares beyond the low anticipated levels already made likely by the effects of the global economic slowdown. Their absence will leave empty seats not just on transatlantic routes but across the world.
Around 9,500,000 passengers a year made return flights between the UK and North America alone in the year to last May. Some 9m travel on scheduled services, the rest on charter jets. That works out at an average of around 26,000 people a day.
However, airlines and travel companies were reluctant to anticipate the effect on passenger numbers. A spokesman for Virgin Atlantic said: "It is probable that these events will worsen the difficult trading environment that we were already operating in. Just how much they worsen it we will have to wait and see."
If things get bad then there will be a reduction in the choice of planes and carriers across the Atlantic and some of the less obvious routes may be axed.
Technological check-in
Ironically, the long-term impact of the atrocities could speed up the introduction of more efficient, hi-tech identity checks on passengers which can make it more difficult for terrorists to slip through the net and to shorten frustrating delays at immigration.
Technology exists to monitor travellers by checking their hands or eyes. The former technique has already been tried out at US airports including New York's JFK. It works on the basis that everybody has a different palm print. The latter, called iris recognition, is due to be tested on volunteer customers of British Airways and Virgin Atlantic at Heathrow's Terminals 3 and 4, starting later this year. It is based on the fact that every iris is unique. Once passengers have registered, their iris patterns are stored in a computer so that, when they look into a camera at the airport, they can be quickly identified. The potential for linking the airport cameras with a database of known or suspected terrorists is obvious.
IATA's Gaillard said: "I think one of the effects of these attacks will be an intensification of efforts to introduce more electronic means of checking identity. We used iris recognition to allocate seats at our recent annual general meeting - and it took about 10 seconds per delegate. Until now the authorities have been interested but not really going full speed ahead. I think what has happened could provide them with a new incentive."
• For the latest advice on travel to the US and every country in the world from the Foreign and Commonwealth Office, see fco.gov.uk. Passengers seeking information regarding British Airways flights to the US should call 0845 7799977. For updated information see theguardian.com/travel.
Click here to read Middle East editor Brian Whitaker's description of a typical check-in on the world's most security conscious airline.
