Per this page: https://www.aa.com/i18n/aadvantage-program/elite-status/elite-status-benefits.jsp
AA elites (Platinum and up) flying on Alaska (AS) get preferred seats.
First I looked on aa.com and found the flights I wanted were $700 for an AA codeshare flight on Alaska metal (plane.) But it was $177 booking directly on Alaska's website. Even though it's a work trip, I couldn't in good conscience book on aa.com and there is really no reason to since it's not like I'm going to get upgraded to first class on Alaska based on my AA status. (AA elites don't get any chances for complimentary upgrades to first class on Alaska)
So I started to book on Alaska. First I entered my AA number on my profile before making a booking, then during booking I selected my AA number instead of my Alaska number: (see lower right)
But when I get to the seat selection screen, I see this. Note I have to pay $17 to select more legroom seats and most of the plane appears unavailable. If I didn't want to pay $17, literally only a few middle seats in the last few rows on the plane were available. Presented with that option, I first made the mistake of paying $17 by selecting a more legroom seat, then I also paid $27 for a premium class seat on the return flight for similar reasons.
But when I got to the final booking confirmation page, I saw this message saying my AA elite status is confirmed and that I may have new seat options available.
So I went back and seats that were previously showing as unavailable (it's not the same flight as the pic above) were now available and even better, more legroom seats were now free.
However, on flights with the new Premium Class, those are not free and are still extra ($27 in this case for a short 1h55m flight) but I was able to select 10B whereas at first only seats at the back were showing.
So since most US airlines allow you to cancel flights within 24 hours without penalty, I cancelled my original flight where I paid for both the more legroom on the outbound and premium class on the inbound and rebooked and got the more legroom seat for free and didn't bother booking a premium class seat on the inbound since I can sit just 1 row behind, although I ended up going with 10B in the hope no one sits next to me. (hope springs eternal in yours truly) I'm sure I'll survive 4" less legroom for a sub 2 hour flight and I should be boarding early based on my AA status anyway.
Thanks to this, I saved $40!!! 😱😲
-As an AA elite, do not pay for 'more legroom' seats or row 6 seats, you'll be able to select this after you purchase the flight
-Also a whole bunch of regular seats will open up in the forward half of the plane
-As an AA elite, you'll still have to pay for Premium class
-Alaska charges any upgrade fees such as the fee for premium class or more legroom seats as a separate transaction, it doesn't say 'upgrade fee' or anything but it looks a bit suspicious if you're going to be submitting expense reports and you're only allowed the cheapest economy fares by your travel policy.