>>>Yes the economics of twins have been proven, except on ultra-long ranges. It's the 777's job to prove it.<<<
So why does the 777LR fly farther, faster, and [apparently] cheaper than the 340NG?
>>>How could Airbus not have the A340? It's filling 10,000 to 16,000 km range section. The A330 can never go this far unless you start putting fuel in the cabin! The A330's wing has less space for fuel than the 340's because it is more reinforced to counteract lift. In the A340 the engines do this job.<<<
Simple. Take a 340, remove two of the engines, reinforce the wing, and add more powerful engines. Would still be capable of the same range, would it not?
>>>By the way, how many airlines are currently operating their 777-200ER on very long routes (10 to 13,000 km)?<<<
Quite a few. But there are very few air routes in the world greater than 10,000 km to begin with.