why would you assume there are positive externalities though?
large airports overwhelmingly serve for-profit airlines and freight carriers. I'd argue a lot of this activity should really be moved to rail. but either way, it seems that the businesses involved should cover the cost to operate.
smaller airports are mostly used by hobbyists. while cool, this is not a particularly accessible hobby, and I don't feel it is worth subsidizing.
the only exceptions I can think of are airfields in remote communities (Alaska, islands, etc), and strategic locations that are desirable to the military.
The fact that it's made it through a somewhat democratic process is plenty of reason to assume positive externalities in the very weak sense of noticing that you should be looking for them. Relying on the assumption for more than that would be silly, of course.
large airports overwhelmingly serve for-profit airlines and freight carriers. I'd argue a lot of this activity should really be moved to rail. but either way, it seems that the businesses involved should cover the cost to operate.
smaller airports are mostly used by hobbyists. while cool, this is not a particularly accessible hobby, and I don't feel it is worth subsidizing.
the only exceptions I can think of are airfields in remote communities (Alaska, islands, etc), and strategic locations that are desirable to the military.