Expanding means a longer runway so that bigger planes can take off and land. Air Canada is currently the only game in town at the Kingston Airport. Once expanded people will be able to travel faster to Ottawa and Toronto to connect to bigger Domestic and International Flights. Travellers will enjoy larger planes and more choices on just who they want to take them to their destination.
From the perspective of the home owners, they are nervous that the price of their homes will go down if larger planes and more of them are travelling in the airspace above their homes.