Originally Posted by
ralfp
Note that US-HND flights do not follow the pattern. There are midnight US departures arriving into HND at 5am or so, as well as ~6pm US departures that arrive around midnight.
Why the difference? I can think of two reasons: lack of curfew and the higher rate of O/D traffic (non-connecting passengers).
Actually this is because HND departure/arrival of international flights are limited to late night and early morning except for a few Asian destinations (Seoul, Beijing, Shanghai, and maybe Taipei). Otherwise you'd be able to connect to virtually everywhere in Japan from HND, while the domestic network from NRT is very limited.