The really annoying thing is that FS doesn't have any generic airport buildings! A limited number of big airports have custom buildings, but the rest of FS's gazillion airports either have generic buildings of kinds that don't belong on airports, or they're small fields that have no buildings at all. The large majority of airports in FS are cluttered with office buildings, apartments and warehouses, but have nothing that even remotely resembles a terminal or a hangar. Aside from those few big airports with their custom buildings, control towers seem to be the only type of generic airport building in the sim.
Maybe the lack of generic hangars and terminals was deliberate, MS's way of inspiring people to create and release add-on airport sceneries.
More likely, MS just forgot to put hangars and terminals in the sim. (sigh...)