A couple of you have asked whether Viewpoint Park (the viewing area at the west end of Seattle's Sea-Tac Airport) is still open. I went down there today to have a look, and the good news is that it is still open, but for how much longer is uncertain. A sign posted at the entrance says the park is to be closed, but the Port of Seattle promises they will keep it open for as long as possible. No date has been set for its closure as of yet, although 30 days notice will be given before it does. The date, when known, will be posted at the park, alternatively it will also be posted on the Airport's website at http://www.portseattle.org. Right now, I know of no plans to relocate the park, and the way airports treat observation facilities in this day and age, I doubt it will happen.
If you're in the Seattle area, or plan to be here in the next couple of months, go down there and have a look. This may be your last chance.