Figures from the Association of European Airlines released in August showed more than 37.3% of all intra-European flights left more than 15 minutes late in June.

1999 'worst year'

It was the fourth time the 30% figure has been broken in the first six months of this year.

The worst case was the newly opened Milan-Malpensa airport where 74.7% of departures were delayed by an average 52 minutes each.

Different centres cause problems

The AEA report said: "There is already enough evidence to hand to mark down 1999 not only as the worst year on record, but the worst by a very long way."

At the heart of the problem is Europe's air traffic control run by 49 centres using 31 different computer centres, argues the European Commission which is due to unveil a report into possible solutions to the crisis later this year.

But it says little can be done unless European Union countries are prepared to cede more power to Brussels-based Eurocontrol.

The AEA's monthly report noted that the figures were affected by flight restrictions caused by the Kosovo conflict.

But it said the lion's share of delays were caused by infrastructure problems, in particular air traffic control bottlenecks.