The Federal subsidy (our Federal taxes) that almost all airports get are to be used to support active flying, not non-flying projects, hence this ruling.
That's one *interpretation* of it...what 5190.6B actually *says* is
"Aeronautical activity is defined as any activity which involves, makes possible, or is required for the operation of an aircraft, or which contributes to or is required for the safety of such operations..."
and
"In accordance with the Airport and Airway Improvement Act of l982, 49
U.S.C. ? 47101, et seq., and the Airport Improvement Program (AIP) grant assurances, the owner or operator of any airport that has been developed or improved with federal grant assistance is required to operate the airport for the use and benefit of the public and to make it available for all types, kinds, and classes of aeronautical activity and without granting an exclusive right."
and
Appendix 1
"1.1.a Aeronautical Activity. Any activity that involves, makes possible, or is required for the operation of aircraft or that contributes to or is required for the safety of such operations.
Activities within this definition, commonly conducted on airports, include, but are not limited to, the following: general and corporate aviation, air taxi and charter operations, scheduled and nonscheduled air carrier operations, pilot training, aircraft rental and sightseeing, aerial photography, crop dusting, aerial advertising and surveying, aircraft sales and services, aircraft storage, sale of aviation petroleum products,
repair and maintenance of aircraft, sale of aircraft parts, parachute or ultralight activities,
and any other activities that, because of their direct relationship to the operation of aircraft, can appropriately be regarded as aeronautical activities. Other activities, such as model aircraft or model rocket operations, are not aeronautical activities."
[Emphasis added]
It is only an *interpretation* from decades ago by the FAA that decided that aircraft construction was not an "aeronautical activity". NOTHING in the definition in 5190.6B precludes it from considered as such.
That definition is likely SO old that nobody even *thought* of aircraft construction...the best they could come up with something "aviation-like" that wasn't suitable for an airport was model rocketry and model airplanes.
I'm frankly surprised that EAA didn't work harder to get the definition modified, or at least the interpretation changed, to include the *actual* building of an "aeronautical vehicle". Well, maybe not so surprised...