This will not start in Australia because of CASA and an aft thinking government, but in another country possibly over the ditch or even an African nation as the test bed by a big Multi or a few combined.
Once the bugs (a few crashes) are sorted, the CASA's of the World will need to be put in their place for governance of manned craft - then their days are numbered as the power they are now. Seems every country has a bit of CASA in its system.
Uber/ Microsoft/ Amazon may join force to bribe enough governments that CASA and the like only need a small airspace sector to govern - Governments need $,s and that aint from petrol/diesel in the future nor from home mounted solar.
Air tax will be that revenue.