Of course not - a huge part of the whole business case for WSI is the 24-hour status and they would not be so stupid as to throw that away by allowing new residential development in the direct/loudest part of the flight paths. There are a small number of existing residents, and the NIMBY's are crowing about how badly it will affect that handful, but the fact is the airport has been planned for decades and these residents will also get money for things like double-glazing. Appropriate use of the direct flight path land is also critical to the planning of new commercial and industrial development in the area, such as Western Sydney Aerotropolis and the new community of Bradfield. Mostly the land directly under the flight paths at low altitude will be used for industrial/logistics which is perhaps the most compatible land use, with some preserved as open space.