Airlines have cut 5.6% of their capacity in Europe for the last three months of the year compared to the same quarter in 2007.
The latest figures from OAG said this was double what it had forecast in August.
The airline monitoring company said the number of flights within the region had also dropped by 5% compared with 2007.
This is also much higher than the August forecast of a 2.7% fall.
The drooping economy also hit flights and capacity in other regions, OAG said.
In the US, there was a 10.6% cut in flights and a 9.2% drop in capacity.
Asia had a 6.5% fall in capacity and a 7.1% drop in the number of flights.
Steve Casley, OAG's chief operating officer, said the figures were "compounded by significant economic turmoil in the global financial markets."
He said the figures were not as dramatic as previous ones but he warned: "With economic problems now impacting both Europe and Asia this picture could change quickly as airlines are extremely vulnerable and quick to react to economic downturns and subsequent shifts in market demand."
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