wrote:

The guy who uses it [the small airport] to fly for $100 hamburgers (or, are they $200 hamburgers these
days?) is getting subsidized without his flight contributing very much to the
economy.

You may be right; on the other hand that $100 (or $200)
got spent. An airplane was built and bought, it was
maintained somewhere (likely on another small airport),
gas was bought and so forth.

Cities more often than not conclude that airports are an
economic add to the community. That's why they fund them.
So does the FAA.

Having said that, governmental decisions are often suspect
and I would like to see a study that addresses the
economic benefit of small airplanes.