It's not just airports but the wider issue of "privatisation" in general of public infrastructure. I have no issue with selling off the Commonwealth Bank or Qantas but I sure as hell do about Telstra's network (as distinct from the phone business), the airports, most motorways and power transmission and generation infrastructure (but not the actual sale of electricity). All of this stuff was built with taxpayer dollars but the proceeds of sale have largely been ploughed into targeted welfare and parish pump projects designed to keep the party who made the sale in power for longer than they deserve.
But to get back to the premise of the thread, the airports are indeed a disgrace under private ownership and I will be interested to see how long Sydney Airport are allowed to string out a decision about whether they are going to build Badgery's Creek or let someone else have a go.