While in game Right-Click on the map and hit "clipboard maps". Then choose a map AA factory/Small field/Port/ V base etc.. Anything that has a name to it (picture next to it, refer to the map key) can be destroyed.
Example: on a Port it will have a picture of a tank next to a hangar, that is the Vehicle hangar and be destroyed.
At an Airfield they will have a picture of a plane next to hangers, these are Fighter hangars.
The ones with Larger planes are bomber Hangers. The tank again is Vehicle hanger.
A map key is on all the maps, in one of the corners.