LONDON: Air carriers British Airways and Qantas have abandoned their proposed merger after disagreement over "key terms" central to the deal, which, if successful, would have produced a global airline valued at £4 billion ($6.1bn; €4.2bn).

Alan Joyce, chairman of Qantas, warned earlier this month that a "number of significant matters" had to be resolved if the proposed tie-up was to take place.

A statement from Qantas earlier this week confirmed the failure of this endeavour, saying: "Despite the potential longer term benefits for Qantas and BA, the airlines have not been able to come to an agreement over the key terms of the merger, at this time."

Observers predict BA will now attempt to pursue a merger with Spanish carrier Iberia, while Qantas is expected to seek to forge alliances with airlines operating in Asia.

Data sourced from Wall Street Journal Online; additional content by WARC staff