WASHINGTON, US - PASSENGERS flying domestic routes in the United States faced a dramatic rise in delays in 2007, according to a report.

Delays were up 29 per cent last year compared to 2006, said the report from George Mason University's Center for Air Transportation Systems Research released on Tuesday.

The delays recorded in the report included postponed flights but also cancelled flights, diverted flights and flights that were over-sold, the report said.

In 2007, 7.4 million flights transported 647 million passengers to 267 airports, a 4.5 per cent increase in passengers compared to 2006.

The average delay for passengers was estimated at 26.3 minutes, up from five minutes the previous year, the study said. And more than one in four experienced a delay.

Flight delays affected 23.9 per cent of passengers, whose average delay of 57 minutes was an increase of two minutes over 2006.

The percentage of passengers on cancelled flights came to 1.8 per cent, with the average delay at 11 hours The number of passengers affected by over-sold flights increased 14 per cent, at 1.14 per 10,000 passengers.

No US airline managed to reduce delays for passengers last year.

'The United States has a very brittle air transportation system,' said professor Lance Sherry of George Mason University and lead author of the report.

'Fewer empty seats on each flight combined with over-scheduling at key airports creates a system that does not have capacity to handle moderate, let alone major disruptions,' Prof Sherry said.

Airports with the most delays included Chicago O'Hare International, John F. Kennedy International, La Guardia in New York, Newark in New Jersey, Dulles International in Washington and airports in Detroit, Boston and Philadelphia.

The US airport network of 'hubs' offers advantages for airline companies but passengers travelling on hub airlines 'were more likely to be subject to long delays', said the study. -- AFP