Seasonal service June to September. One idea is to fly in to SEA and back from Vancouver or Calgary. The rail journey Seattle - Vancouver can be spectacular* but slow, as can the trip through the rockies to Calgary. Many options including luxury (and non-luxury) trains, organised tours etc.
Be careful though, none of edelweiss’ flights are daily.
Flights are codeshared with Swiss so you can book connecting flights from Geneva using them.
Really? Just checked some random days for next summer on Skyscanner. Seattle direct is 930 return while cheapest is 630 but has 19 hrs layover in Keflavik … which means you need a hotel room.
Flights to North America are dirt cheap. We went to US East coast not long ago for 450 per person, Swiss direct from ZRH. The bigger issue are the costs once you are over there