they can all be shut down if complainants get smart
Not so much.
Firstly, nearly all airports are protected by "pre-existing use" rights. Secondly, councils (despite what they pretend to have) actually have little power. Its with the State Governments.
And private individuals have the same right to "garage" an aircraft on their land as a car. This is untested here (because it hasn't needed to be tested) but the same legal precedent that allows you to park a car on your home protects your right to park an aircraft on your land.
The greatest threat is weak airport owners and property values.