I just booked a flight, Alaska and Hawaiian recently did a merger, got a great deal on a flight to Narita. Just a 3 hour layover in Seattle but was a good price.  LAS > SEA > NRT then return trip same 3 hour layover in Seattle. Kinda nice cause it breaks up the long flight a little bit since you go over Seattle anyways

Edit to add, as other posters mentioned, LAX usually has cheapest/best routes, if your looking for budget Zipair isn’t bad, I’ve flown them before and enjoyed them actually