Alaska Airlines, Southwest and jetBlue are currently battling over the New York to Seattle route — net result? Awesome prices on Non-Stop flights that we don't see often at all.
While generally the Alaska / jetBlue flights are $20-$40 cheaper than Southwest, Southwest DOES have two free checked bags (so that may well be cheaper for you if you are bringing tons of boards like I generally do).
Ikon Pass holders ski/ride free at the Summit@Snoqualmie and Epic Pass holders ski free at Whistler.
NYC (or Newark) to Seattle, Non-Stop, almost always runs $375 — these cheap ski trips save 35% and get you there Non-Stop on Alaska Airlines or jetBlue.
Generally you need to take at least one stop in each direction to get a flight to Seattle anywhere near $300 — let alone below it. That said competition between airlines is a positive thing for all of us hoping to ski the pacific northwest this winter (as is getting out to the left coast without a lay over).
Whether you make the drive up to Whistler via the Sea to Sky Highway (did it last year, planning to do it again this year!), Mt. Baker, one of the local Seattle hills (ie. the Summit at Snoqualmie) — or maybe feel like skinning the Alpental Backcountry (full write up in Powder Mag) — it's really hard not to score.
Particularly now that The Summit at Snoqualmie has been added to the Ikon Pass. If you picked the Epic Pass like I did that probably means your best option is to cruise up the coast to Whistler.
Add a Night in Seattle
If bringing the lady friend (or you are one) my suggestion would be to add a night in Seattle before heading for the hill. Hit Pikes Place for Coffee (Ghost Alley Espresso rules — get the Dirty Chai), browse the flowers, and then crash at The Lowes Seattle.
Here's my view of my better half / digital marketing girl boss picking her favorites — before we jumped in the A4 and headed north to Vancouver:
The oyster bar downstairs — connected to The Lowes — has both an amazingly cheap Happy Hour (that kicked off right as I walked in last spring) AND a straight up amazing breakfast / brunch. It's a little pricier (200/nt-ish) but you seriously can't go wrong, the place is at least as nice as the insane expensive $600-800 a night rooms in NYC imo.
Booking on Southwest
So unlike jetBlue and Alaska who let us link to their site — Southwest does not. For anyone who is thinking of bringing at least one checked bag their flights are likely the cheapest ($244 RT with One-Stop) since you can bring two bags (or one bag PLUS a ski bag and a helmet/boot bag).
That said you should look at the Southwest Low Fare Calendar. Enter La Guardia (LGA) as your origin and Seattle (SEA) as your destination.
Look for the $127 each way prices. If you are traveling light you will likely save a few bucks going with jetBlue or Alaska via the links below:
More availability is out there so if the dates you like aren't show above do a little digging on Google Flights.