It is argued that efficient airports are a necessary ingredient to economic well-being.
Airports, however, are not viable on the basis of their aviation revenue alone and depend on income from car parking, retailing and hospitality to create sufficient income and profit to justify the capital expenditure required to build and maintain them. Even so the margins are small.
For example it may be that new airports cost more to build than their own economic value can justify. The balance, however, should be filled by the economic benefit they project onto the economy in general.
However, the private sector will not fund a non-viable entity, which leaves the state to finance the difference and at the current time many states are disinclined to provide this funding which could leave many developments unable to get off the ground.