The greatest threat is weak airport owners ... and property values.
Perhaps one should reconsider that statement... the greatest threat imho is the weakness of the industry as a whole, its unwillingness to support its own and ongoing refusal to relinquish its egoistical stance of arrogant self righteousness.
This is untested here
If it were to be tested, I don't think I am far from the highly likely prediction that the airport owner would have insufficient resources to deal with a well organised gang of complainers/developers/pollies...etc in cohorts. An airport owners primary revenue is certainly nowhere near what a commercial/residential development might command. The industry might well find itself with a precedent set for them without them even knowing it. They may well successfully argue that the vast majority of airfields in Australia are now redundant. There is certainly only a small number that have any RPT services. The rest are a pure convenience or playgrounds for those with a hobby...
Further, there is nothing to say you can't park your aircraft here... but whether you can land or take off is a different story.
Like I said... unless protection is afforded at the Cwlth level.