Ancient Greek - I agree, Australia's "National Airport" should be centrally located too as should the USA's, Russia's and China's - that would be so convenient for so many people
The airport is located in the south east because thats where the people with the greatest propensity to fly are located (and by a significant margin) - now it can be argued, of course, that those with a high propensity to fly have congregated around the biggest provider of flights thus creating a gravity spiral of demand and supply - which is true, but that is the economic history of the UK over that last 6-7 decades and has already been written. One additional runnway (if we get it) can only address the demands of today and the immediate future, it is nowhere near sufficient to re-map the economic geography of the UK and even if it could that would take many decades. Show me a government with that kind of vision if you can..!