Originally Posted by MaxVO

For the flights going west against the prevailing wind direction, I can't imagine that avoiding the polar route would somehow save on fuel. However that could be done with the opposite intent -- i.e. to test endurance and limits of the new aircraft (A351). Still that's typically the job of Airbus, not a customer airline with paying pax on board. Any "wind" theory along would also not explain such persistent avoidance of Russian and Chinese airspace.

Nicc HK's ideas from Post 2 make sence (i.e. Russian overflight fees, and air force priorities). I suspect those conditions would not affect CX alone. What other airlines normally fly the polar route, and are any of those flights still operating right now? They might provide the confirmation for or against the above hypothesis.