This move would allow passengers to earn and redeem Alaska miles on all Oneworld airlines, along with other perks.

Photo: Alaska Airlines
Making the announcement on its website, the major American airline has said that it plans to join Oneworld next summer. It also said that it would strengthen its partnership with American Airlines, which is also a member of the airline alliance.
As of February 14, travelers are able to redeem Alaska Airlines miles on all American Airline flights. In addition, Alaska Lounge members are able to access American Airlines Admirals Clubs. By spring, Alaska miles can be earned on all American Airlines flights.
Should Alaska Airlines finalize its membership with Oneworld, passengers will be able to earn and redeem Alaska miles on all Oneworld airlines, as well as enjoy privileges such as priority boarding, premium seating, and baggage benefits on any Oneworld airline—including British Airways, Qantas, Cathay Pacific, Finnair, and more.
Passengers on Alaska Airlines can also look forward to accessing 650 member lounges with MVP Gold or MVP Gold 75k status.
More information here.