Yes, the studies are a joke, and are rigged. Generally performed by
consultants paid for by the industry. Its similar to when Boyer calls for
the AOPA do do an unbiased study of user fees. LOL.

The "studies" mostly look just a gross payroll at the airport (some even
include the businesses that located on or near airport property -- as if
these would not exist w/o the airport) and then spinoff spending (the
hamburgers and such consumed by the fliers and their hapless passengers).
For small GA airports in areas already accessible by rail or roadway, the
economic benefits are negligible to negative.

None of the studies looks at the opportunity cost of the foregone land,
the external costs of pollution (air, water and noise), etc. If these
damned things were such economic engines, why on earth do they need annual
operating subsidies from the FAA?