We just flew back into Seattle from Puerto Vallarta and used a trick to save a lot of time. If you have a smart phone, make sure you download the free app called Mobile Pass. You fill out all your information for your passport, and as soon as you touch down in Seattle, you transit the request for the airline you came in on, and will get a confirmation scan code in under a minute or so.
Now when you go to customs, you don't get in the line where the hundreds of people are going through the Kiosk Entry machines, because if you start that too, your Mobile Pass can't be used. Instead you will see you get to go through the same lines that the airline crew goes through. The line says above it for Airline Crew and Mobile Pass. Your just show your confirmation to the attending person and they will have you scan that confirmation code you got back, and then send you through. People look at you as you sail by, trying to figure out how you did it. After you pick up your checked bags, you will again see the same kind of expedited exit for Airline Crew and Mobile Pass. Saved SO much time! We were at the very back of the plane, and still beat everyone out of the terminal. When you download the app, you will several other big cities have started adopting Mobile Pass too.
Other airports currently supported are:
ATL - Atlanta
MIA - Miami
ORD - Chicago
SEA - Seattle
SFO - San Francisco