CANADIAN Airlines and BritishAirways will end their codeshare and frequent-flyer co-operation on June 1.
The split follows Canadian’s buyout by Air Canada earlier this year.
Canadian will also leave Oneworld, which it helped found, and join Air Canada’s Star Alliance.
The chairman of the Oneworld governing board and chief executive of American Airlines Don Carty said the alliance will continue to offer benefits to passengers in Canada through other airlines.
Oneworld has recently opened a management office in Vancouver.
The departure of Canadian leaves the global partnership with just six core members: BA, American, Cathay Pacific, Qantas, Finnair and Iberia. Aer Lingus and Japan Airlines are set to join this year.