As someone who has lived in both the US and OZ, working for what some might term “top of the list” airlines, I’d just like to add the following.....
Firstly, regardless of what some online calculator tells you, the taxes are less in the US and almost everything you need or have to spend your salary on, each month, costs less than it would in Australia. Do not make the mistake of comparing AU$ to US$. It’s only a small part of the equation.
Secondly, do not underestimate the collective resistance to anyone other than a US citizen or Green Card holder, ever being employed by a legacy airline. My personal feeling is that it might happen if hell freezes over first. In other words..never.