This is what the Wikipedia listing has to say on the subject, for what its worth... not sure if this helps or misinforms the discussion here ! (Vietnam Airlines certainly gets a mention here, btw) :-

Possible future OW members

Oneworld has expressed its desire to recruit new member airlines while several airlines have expressed their intention to join the alliance.

* Brussels Airlines - The airline expressed its interest to join one of the major airline alliances, considering it a priority for the airline. However, a potential purchase by Lufthansa may stop it from joining oneworld. The airline has codeshare agreements with American Airlines, British Airways, Finnair and Malév Hungarian Airlines.

* China Eastern Airlines - The airline has been courted by Oneworld and currently codeshares with American Airlines, British Airways and Japan Airlines. However, Air France and China Southern Airlines are lobbying at the airline to join SkyTeam.

* Grand China Airlines - The airline was previously known as Hainan Airlines has expressed interest in joining Oneworld and has codeshare agreements with Japan Airlines and Malév Hungarian Airlines.

* S7 Airlines - The airline was in negotiations with British Airways in 2007 to possibly join the alliance in the near future.

* Vietnam Airlines - Current member Japan Airlines has expressed a desire to sponsor Vietnam Airlines for a membership to expand the oneworld network in Southeast Asia. The airline currently codeshares with American Airlines, Cathay Pacific, Japan Airlines and Qantas. However, the airline is said to also have discussions about the possibility of joining SkyTeam.

* Canada WestJet - currently in talks with Oneworld to possibly join the alliance in the near future. This would fill the void left by the departure of Canadian Airlines. However, WestJet recently announced a pact with Southwest Airlines which would include codeshare agreements and frequent flyer reciprocity.

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