Holiday travellers face another torrid summer of airport delays - but just how bad will it be? The Association of European Airlines warns that more than one third of flights could be held up across the region as a whole. But the UK's air traffic control organisation aims to keep it down to one in 10.

Either way, it looks certain to be worse than last year. The AEA bases its pessimism on this year's performance so far. In the first three months, its members reported 23.9% of flights delayed by more than 15 minutes. At Madrid, the worst hit of Europe's major airports, the figure was 36.4%.

The target set by Brussels-based Eurocontrol, which oversees the flow of flights across the region, is that punctuality this summer should be no worse than in 1997. But according to AEA secretary general Karl Heinz Neumeister: "Our first quarter figures are already worse than in the peak of the summer period in that year."

Meanwhile, Britain's National Air Traffic Services has warned airlines that the holiday peak this year will be "challenging" as it struggles to provide enough controllers to cope with the rush while training some of them to work at the new en route control centre at Swanwick.

Charter passengers, as usual, will bear the brunt, not least because package holiday airlines cram as many flights as possible into the day to keep costs down, leaving them vulnerable to a chain reaction if one departure is heavily delayed. Civil Aviation Authority statistics, gathered from 10 British airports, show that 72% of scheduled services were on time last year, compared with only 53% of charters, and that the average length of delay was 13 minutes and 38 minutes respectively. Eurocontrol expects those between Germany and the Mediterranean to be worst affected. That could also hit British holidaymakers if serious congestion snarls up Spanish airports, for example.

Two faintly optimistic notes sound through the gloom. One is that, while UK controllers will handle a record number of flights this year, the economic slowdown suggests the increase will be smaller than expected.

The other is that while the proportion of charter flights delayed for more than one hour has risen in the past five years, it has crept up rather than soared, from 16% to 18.5%. But it is not much to cling to. Take a good book to the airport - or make sure the Scrabble is in your hand luggage.