The top 10 airline routes in the world by how much capacity is scheduled are all generally in the Asia Pacific region. That includes the Mideast (Saudi Arabia’s domestic Riyadh – Jeddah) and it includes Australia (Sydney – Melbourne).
There’s not a single route in the top 10 in the U.S., Canada, or anywhere in Europe. A decade ago South America featured once – Sao Paulo to Rio – but that’s no longer in the top 10.