All airports have capacity constraints, there's the limit to how many planes can take-off/land, but also with how many gates and maintenance facilities they hav

All airports have capacity constraints, there's the limit to how many planes can take-off/land, but also with how many gates and maintenance facilities they have. I actually support the idea of shifting some of this capacity to nearby airports, especially if it results in lower fares for passengers. If I'm generous with their intentions, Australia were probably trying encourage tourism to smaller cities, bring business to local economies, increase competition on quieter routes, etc. Unfortunately it seems Qatar thought it easier/cheaper to fly the last leg empty instead of marketing tickets to the final destination. For what it's worth, I actually flew London-Melbourne-Adelaide earlier this year. I booked a separate flight for MEL-ADL since it was cheaper than booking the whole trip through a single carrier.