The 777X is a program, covering two (or more) models: the 777-8 and 777-9. The one that flew yesterday was the first 777-9 -- a replacement for the 777-300ER, with significantly increased range, a stretched fuselage (it's slightly longer than the 747-8), and up to 426 seats. Increased use of lightweight materials and those whizzy folding winglets mean it's no heavier than its predecessor.
Maximum cargo capacity is roughly three-quarters that of a 747-8 by weight.
There's also a possible 777-10X model that will seat up to 450 passengers and is being pitched as a rival to the A-380 superjumbo.
The real miracle here is that the big four-engine jumbos are being replaced by a twin-jet. (This says something profound about advances in engine technology since 1970. Or even 1990.)
Maximum cargo capacity is roughly three-quarters that of a 747-8 by weight.
There's also a possible 777-10X model that will seat up to 450 passengers and is being pitched as a rival to the A-380 superjumbo.
The real miracle here is that the big four-engine jumbos are being replaced by a twin-jet. (This says something profound about advances in engine technology since 1970. Or even 1990.)