Wife and I are planning a trip. We have been out west several trips and always take a couple pistols.
It just dawned on me that this may not work on this trip. Is it legal to fly into Washington with a checked pistol???

Yes, you can. Firearms are not verboten in WA (yet).

Critical laws you should know -
1. CC is not permitted w/o a state or reciprocal license.
2. CC and/or loaded pistol is not permitted in a vehicle, unless you are going to/from an outdoor activity (hiking/fishing/hunting/etc).
3. No duty to inform officers you have a firearm
4. Signs do not have force of law

RCW 9.41 is the relevant section on weapons, if you want mind-numbing reading. WA has also expanded the prohibited places w/ a permit.

Keep a pair of nail clippers handy. SEA TSA uses the big ass ziptie on firearm cases. Unless you check a bag with a knife, it's a PITA. Asshats.

@mikeyb76

Thank you for that reply, I was rethinking this trip.
So do you have to open carry if hiking, etc.?

Are you are a Utah Permit instructor?

Garden-variety pistol is fine. Threaded barrel would likely make it an "assault weapon". It's not a federal mandate to enforce state laws, although that's not a guarantee you wouldn't get hassled.

ETA: mags with 11+ capacity are also a potential problem due to the above.

Seatac TSA on the way out generally seems more interested in wiping all your stuff down so they can justify the cost of their expensive explosives residue testing machine than in looking closely at the hardware. The last time I went through they tried to get me to put locks on my soft pistol case instead of the hard case as mandated by regulations and stated on the declaration I signed.

Not an instructor; I spent 46 years in WA.

WA is an open-carry legal state, with restrictions on locations (visiting the RCW would help, or places like handgunlaw.us). Conceal carry (and vehicle loaded carry) are only possible with gov't permission (CPL permit). There is an exemption for concealed carry/loaded carry in a vehicle that you do not need a permit for, and that is when you are on your way or coming back from a "legitimate" outdoor activity, like hiking, hunting, fishing, etc.

Fun fact: Wife & I drove up to WA for my niece's grad party this past weekend, going through UT, ID, OR, and WA (1600mi in 36 hours). I was not concerned.

Just make sure that your case has padlocks in all the holes on the case. Airlines state cases must be padlocked, but they don't say how many, until you're checking it.

If you are going to, engaged in, or coming from an outdoor activity like hiking, you may carry concealed without a license/permit.

At all other times you may carry openly without a license/permit.

If you are in a vehicle you are carrying concealed even if it's in plain view, so carry in a vehicle requires a license/permit if you are not going to, engaged in, or coming from an outdoor activity like hiking.