Cumbria Chamber of Commerce has written to Carlisle City Council supporting Stobart Air's redevelopment proposals for the city's airport.
Stobart plans a freight warehouse and new headquarters for the Stobart Group, based in Carlisle, as part of a £20m upgrade. The plans were reduced in scale and resubmitted after an earlier application was called in for public inquiry.
Rob Johnston, chief executive of Cumbria Chamber of Commerce, said 560 businesses had registered support for the airport's growth. He added: "It's clear that this issue is now broken down into two areas: the future development of the airport and the retention of Stobarts in the Carlisle area.
"Over the past three years, the chamber has engaged with the business community on the airport, including most recently in November 2008 in an independent online survey. The absolutely overwhelming position of these businesses is in support of the development of the airport as being helpful to them as businesses and a real issue in demonstrating that Cumbria and south west Scotland are on the business map."
Carlisle City Council is due to decide on the application in December. Cumbria County Council backed the plans earlier this week.