Originally Posted by
night718
They're probably sharing the plane between DC and Houston.
If you look at the new schedules for DC and Houston, NH2 and NH173 matches up. Same with NH174 and NH1.
They don't match up because flights to the US arrive in the afternoon and flights from the US leave in the morning (as is tradition). It looks like planes from HND or NRT overnight at IAD or IAH and then fly back to either HND or NRT the next day. Then ANA just has to do shuffling among its various 789 routes on the Japan end. I imagine ANA still needs to park a bunch of planes and it's cheaper to do that in the US than in Japan.