The curious case of the declining "golden triangle"

In Australian aviation circles, the “golden triangle” refers to the high-volume domestic routes between Brisbane, Melbourne and Sydney. In 2019, these three routes accounted for 28.7% of all Regular Public Transport (RPT) domestic traffic in Australia.

Melbourne-Sydney alone accounted for 15.0% and by any metric is one of the busiest and most lucrative routes in the world. While substantially smaller, Brisbane-Sydney and Brisbane-Melbourne are still the 2nd and 3rd largest routes in the country, accounting for 7.9% and 5.9%, respectively.

RPT refers to scheduled airline services in Australia that are available to the public for purchase. This excludes charter flights, including FIFO mining charters that are a significant portion of air travel in Australia. FIFO flights are not available for sale to the public and rarely serve major routes, rather serving remote mine sites.

The dominance of triangle isn’t surprising given the concentration of population around the physical triangle forms by the three cities. The broader metropolitan areas of these cities accounted for 51% of Australia’s population. In fact, their dominance in Australia’s population results in the “center of population” lying just to the west of the “triangle” near the town of Ivanhoe, NSW.

What is surprising though is how the dominance of the triangle has waned in the aftermath of the COVID-19 pandemic. This wasn’t a slow or consistent decline, but what appears to be a structural downward shift.

In the 12 months to October 2025, the triangle represented 26.7% of domestic passengers, with a relative peak of 26.9% in April and May of 2025. This is significantly lower than the the 28.7% in 2019, and the relatively peak of 29.0% observed for several months in late 2017 and early 2018. Not only is the current proportion lower than the pre-pandemic period, it’s the lowest recorded since the late 1980s, before the deregulation of the Australian domestic airline market.