Most airlines seem confident they can deal with Y2K, but some are taking no chances.
If you find yourself in Warsaw on 31 December this year, don't count on getting a flight home on the Polish national airline. Until 2 January 2000 LOT will ground its fleet to avoid falling prey to the Millennium Bug. But the Polish airline is in the minority. It was the only airline out of 30 I questioned to admit to alterations to its schedule because of potential problems caused by the failure of computer systems to recognise the year 2000.

The midnight hour is being avoided by five others among those I talked to. Britannia, Airtours and Jersey European Airways say there is "no demand". Caledonian wants to offer staff the "once-in-a-lifetime chance to celebrate a millennium".

El Al would not be flying anyway, since the Israeli national airline does not fly on the Sabbath (between sunset on Friday and sunset on Saturday, which effectively rules out flights up to about midnight on Saturdays). A spokesman for the airline, Daniel Saadon, says candidly: "We're very lucky that 1 January 2000 is a Saturday, so we don't have to make a decision."

Fourteen carriers are going ahead with all flights (among them Lufthansa, Air France, Canadian Airlines, Qantas and Aer Lingus) while the other nine are waiting for the green light from information technology departments and head offices. British Airways is not concerned about its readiness (its millennium compliance programme started in 1995 and has had pounds 100m lavished on it) but BA says that a full service over the millennium period cannot be guaranteed.

Young airlines such as Go (aged one year) and easyJet (four years) have systems that were compliant "from birth"; major airlines such as Air France and Canadian Airlines claim to have passed initial tests.

Yet just because an airline's own systems are "clean", it does not mean there are no other digital pitfalls. There are worries that some minor airlines have started their programme "pretty late in the day".

"It's a humungous project," says Updesh Kapur of Virgin Atlantic. "One flight relies on 3,000 computer-related parts."

The web of software support means suppliers need to work closely with their clients, especially on ground-support services. A Britannia spokesman cited baggage loss and gridlocked traffic as potential scenarios, preventing staff and passengers getting to the airport. Then there is air traffic control.

"It is out of our control," says a spokeswoman for BA. Many airlines have questioned the reliability of systems in the Middle East, Central Africa, South America and Eastern Europe. These are zones that, even without a potential software crash, have proved to be "difficult flying", according to Norwin Abl of Austrian Airlines. Mr Abl, who flies himself, thinks that pilots should have the requisite training to deal with the situation, should the systems fail. The International Air Transport Association will publish a report in the summer on the state of air traffic control systems around the globe. At least then airlines will know where their pilots are likely to be flying blind at a minute past midnight on 1 January.

Although some airlines cite low demand as their motive for failing to schedule flights over Y2K, travel agents are selling fast. "Our advice is book now," says Beverly Sams, of Thomas Cook Flights Direct. "The cheaper fares have gone." Long-haul carriers are capitalising on demand for exotic locations: BA and Virgin flights to New York are up pounds 60 on the rates charged last year, while Qantas flights to Sydney are being quoted at pounds 1,431- a pounds 329 rise.

Also, high-season prices will stay high and will not dip, as they usually do, between Christmas and the new year.

Airline Checklist:

Airlines which will not be operating between 31/12/99 and 1/1/00:

Airtours, Britannia, Caledonian, El Al, Jersey European Airways, LOT Polish Airlines.

Airlines which say they will be sticking to their schedules:

Aer Lingus, Air Algerie, Air France, All Nippon Airways, American Airlines, Austrian Airways, Canadian Airlines, Czech Airlines, Iberia, Lufthansa, Meridiana, Qantas, SAS, Turkish Airlines.

Airlines whose precise schedules over the millennium are still to be confirmed:

British Airways, British Midland, Delta, easyJet, Go, Malaysia Airlines, Pakistan International Airways, Royal Air Maroc and Virgin Atlantic.