Newcastle Airport says an independent Scottish government could damage the region's chances of attracting new routes.
The SNP has indicated it would like to cut the level of Air Passenger Duty (APD) if it wins independence in a referendum in 2014.
Graeme Mason, the airport's Planning and Corporate Affairs Director, says if APD is cut north of the border, passengers could choose to fly from Edinburgh and Glasgow instead of Newcastle. In turn, airlines could choose Scottish airports over English ones for new routes.
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Many areas dry over the next few days with variable cloud and cooler airflow
A dry day with bright or sunny spells. Rain comes through overnight into Sunday morning, before drier yet fresher weather develops
A look ahead at the forecast for the Tyne Tees region.