Both airfields & vehicle bases use the same kind of supplies: "Airfield Supplies". They shorten the downtime of destroyed ordonance, ack guns, radar, fuel & troops. They don't have any influence on hangars.
To check if a field is in need of supplies, shift-rightclick the base on map.
Vehicle supplies are for GVs only.
The maproom is indicated as a yellow dot on the map. Also you can rightclick on map, and select "clipboard maps". There you can see the layout of bases, including maprooms. Airfield's maprooms are in the town nearby, a port's or a VField's maproom is right on base.
And yes, goons have the same icon like any other plane, so keep 'em low. Really low, hug the trees. Also it's usually a good idea not to fly the direct path between your and your enemies base. But be advised, some experienced players are actually quite good ad guessing where a incoming goon might circle
