Does someone know why Cathay Pacific and other airlines use different codes for airplanes than what Boeing has listed? For example they list a 777-367 which seems to be a variant of the 777-300 but I can’t find any information on what makes it a 367 vs a 300. Is that just the code that CX uses for the 777-300s they own? I also notice they have odd ones like A321-251NX, A330-343X and such. So what do those non-normal model numbers mean?
The numbers denote the specific variant, like the engine type and max take-off weight. Airbus has the NEO series (new engines) so they add the N. They’re just all model identifiers, like your car may be a GT or XLT or SE.