It's likely an AA codeshare on Alaska aircraft, as AA does not fly that route. You'd also have the option of crediting your miles to an Alaska account, and they have plenty of partners, if you elect not to put them on AA or QF. You might want to look at the Alaska website for a list of their partners.

A lot depends on how often you're going to fly, and if you'll fly enough to accumulate miles for award tickets. SFO-SEA is only 678 miles so there's not a lot of miles to be gained there. If you credit QF tickets to AA, you'll only get 50% credit on discounted tickets. There's a lot to look at, and it all revolves around what your travel patterns will be (and I have to admit I know nothing about the QF or NZ programs, which might be worth looking at).

As to miles, they go in the account of the person actually doing the flying.

If you're in Seattle Aug 4-5 we do have an FT event there--see Community for details.

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