Every few months, a graphic or blog post goes around social media showing the world’s longest flights. It’s enticing since ultra long haul travel is intriguing and ever evolving with new flights stretching the limits of aircraft and our imagination. Australians have always had skin in this game as the country’s isolation has meant that many of the ultra long haul flights have been to/from Australia.
Typically these lists measure the great circle distance between two points. But this can be very misleading. Just because a flight covers a larger distance doesn’t mean it’ll take longer to fly.
The most significant confounder is weather: for example, Qantas’s Perth-London flight has a scheduled block time of 17:50 westbound but just 16:30 eastbound. The difference between these two estimates is the jetstream that generates a headwind on the westbound leg but a tailwind on the eastbound leg.
We might call this the macro-level weather, however flights are also affected by day-by-day variations in weather. For example, despite a scheduled block time of 15:45, over the last year Air New Zealand’s Auckland-New York flight has actually taken anywhere from as little as 14:35 to as much as 16:35 to fly, with an average of 15:12.
This doesn’t even account for airspace challenges. Not only does Qantas’s Perth-London flight have to navigate for the most favourable weather conditions it also has to navigate significant airspace challenges. At present, Iranian, Russian, Ukrainian and Syrian airspace is not available to them, requiring a substantial devision from the great circle route.