Air France-KLM and its US partner Delta Airlines said yesterday they planned to launch a new joint venture to operate transatlantic flights and to share costs and revenue.

The deal would extend an earlier cooperation agreement worked out in March 2008 by including routes operated by KLM, a Dutch carrier, and Northwest Airlines of the United States, which merged with US rival Delta last year.

The new arrangement would cover routes between the US and Europe, Amsterdam and India, and North America and Tahiti in the Pacific, the two carriers said.

The new venture would account for cover about 25 per cent of the transatlantic market and is "an essential element to competition with the two other major alliances active" in the sector, a joint statement said.

The competing tie-ups are Star Alliance, grouped around Germany's Lufthansa, and OneWorld, of which British Airways is the principal player.

The new Air France-KLM-Delta alliance would have annual sales of around $12 billion and offer more than 200 transatlantic flights, or 50,000 seats, a day, according to the statement.

Delta Airlines is the world's largest carrier in terms of traffic while Air France-KLM is number one in Europe.

The Franco-Dutch company this week said it suffered a loss of €814 million in the 2008-2009 fiscal year and would have to cut around 3,000 jobs. Air France-KLM employs 104,000 people worldwide.

But the company's operating loss, at €129 million, turned out to be less severe than the €204 million forecast by analysts.

As a result, Air France-KLM shares rose more than 15 per cent in early trade to €11.12 on an overall Paris market that was 0.43 per cent stronger.

"Air France-KLM predicts that the macroeconomic environment in the first half of the year will remain uncertain and difficult" while the second half should see "some signs of stabilisation," analysts at CM-CIC Securities said.