Once you’ve added an airspaces you have to option to configure how each one is displayed in Gaggle. Simply tap the airspace that has been installed to open the configurator for that airspace. From the configurator you can choose if the airspaces should be used (enabled) or not, which airspaces classes are displayed, and the color that will be used to render each airspace class.
Tip: To see what your changes will look like open the Airspace Viewer to and browse around the map to see how the airspaces are rendered.