With China Southern leaving the SkyTeam alliance next year American Airlines — which owns a $200 million stake in the Chinese carrier — will be expanding its codesharing relationship next year. Along with that will come reciprocal mileage-earning and redemption and reciprocal lounge access.
Ultimately this will be a huge net add for AAdvantage members looking to travel to Asia, unless dominoes fall further and eventually push Cathay Pacific out of oneworld. That would not be a worthwhile tradeoff.