Singapore Airlines did something shocking many years ago. It took its nearly new A340-500 aircraft and put an all business class cabin in it. Then it flew this airliner from Singapore to New York City (Newark) on a regular schedule.
This has been a flight of 9500 miles (or 8300 nautical miles) which, when you think about it, is really quite amazing. The flights are sometimes a bit longer than that because they fly an air track that is most efficient, not always just a great circle polar route.
But Singapore is dropping the flights. The aircraft used is a 4-engine aircraft that never made much economic sense for most airlines and it is probably becoming too expensive to operate this aircraft even on this route.
Will it be replaced? It’s always possible but there are no plans to do so today. A 777-200LR could fly the route with more passengers but who says there are more passengers who want to fly that route? A 787 cannot fly the route today and there are no models with enough reserve distance in them to make that possible. So, as a route, it’s probably gone.
The next longest route is Sydney-Dallas/Fort Worth at 7500 nautical miles and it’s notable that that aircraft is also a 4-engine airplane: The 747-400ER.
The reason both of those are flown with 4-engine aircraft is that they have both the range as well as the ability to fly the most efficient, direct tracks. Two engine aircraft such as the 777 always operate under ETOPS rules which often require slight deviations to stay within range of a diversion airfield.
I do think we’ll see a flight of 8000 or more nautical miles some day in the future. I do not think we will see that flight in the next few years. At the end of the day, such flights are really one-offs that will come and go as demand changes.
Just like the Concorde, it was nice while it lasted.