British Airways parent IAG acquired Aer Lingus and the Irish carrier is expected to ultimately join oneworld and the transatlantic joint venture with BA, Iberia, Finnair and American.
Aer Lingus is a former member of oneworld — they left nine years ago to pursue a strategy as a low cost carrier. Since then they’ve built back their premium offerings. They have a good transatlantic business class, considering the short flights between Dublin, Shannon and the East Coast of the U.S. which are their bread and butter (though not exclusive) destinations.