Air Canada Seattle-Hong Kong $479 to $509 Jan-April 2015 is a deal available today. The fare is $509 for January 19 to February 2, 2015 departures, then drops to $479 for most dates in February, March and April through April 30. Month of May fares rise $250. [Update: Delta Airlines has similar round trip fare at $483 flying YVR-SEA-HKG.]
This flight routes Seattle to Vancouver, then Vancouver–Hong Kong nonstop.
Here is a sample booking with 24 hours in Vancouver for the outbound and an overnight at YVR on the inbound. There are flights without overnight available for a few dollars less.
Air Canada K class, $486.08 SEA-HKG round trip with overnight in Vancouver each way.
The overnight is an itinerary most travelers would likely avoid. I like the idea of an outbound night in downtown Vancouver to walk my legs in the city and parks before a long-haul flight to Hong Kong.
On the return flight, a night at a Vancouver Airport hotel reduces the airport rush with far less probability of missing the flight to Seattle by a Hong Kong arrival delay.
The YVR-HKG flight is 12,700 miles round trip and that is a good haul in miles, even for a base flyer. Looks like K deep discount economy class screws you down to 25% United Mileage Plus miles for the SEA-YVR segments, but you get 100% miles for the HKG flights. United Mileage Plus mileage accrual for Air Canada partner flights. SEA-YVR is minimal distance so the Hong Kong segments are the ones that truly matter for mileage earning.
The changes to Mileage Plus earning based on ticket price beginning March 1, 2015 apply only to United Airlines issued tickets. Air Canada flights purchased via Air Canada website or a third-party OTA like Expedia will earn 100% miles with Mileage Plus, based on distance flown.
This looks like a great deal for Hong Kong with plenty of dates from January through April to plan a trip.
Update: keitherson, a member of FlyerTalk, pointed out possibly an even better deal flying YVR-HKG via Seattle on Alaska and Delta for $483.
Delta YVR-SEA-HKG $483