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.
More top news
Heavy rain expected, also some snow in the forecast
Often very windy, especially as we head into Sunday, with rain or showers. Met Office 'Be Aware' warnings have been issued
Here is our essential guide to all things Christmas in the North East.