French airport operator ADP Thursday said traffic dropped 5.6 percent between January and September and added it aimed to keep its underlying earnings stable this year against 2008.

"For the January-September period, we are at minus 5.6 percent," ADP CEO Pierre Graff said on the sidelines of an event held at Roissy, just outside Paris.

He said traffic fell 4 percent in September alone.

Traffic for the whole of 2009 would fall between 4.5 percent and 6.5 percent and earnings before interest, tax, depreciation and amortization (EBITDA) would match that of 2008, Graff said.