By Michael Shields and Marcel Michelson ZURICH, March 26 (Reuters) - The new Swiss airline, replacing failed Swissair (SWSZn) as flag carrier from March 31, chose American Airlines (AMR) as its transatlantic partner and wants to join the Oneworld alliance, it said on Tuesday. The move means Swiss is keeping the main code-share partners of its stricken forerunner Swissair, while abandoning the over ambitious Swissair-led Qualiflyer alliance project that was a major reason for Swissair's financial collapse. Swiss, built out of former regional carrier Crossair (CROZn), was widely tipped to team up with American -- the world's biggest airline -- and join Oneworld, but a number of regulatory obstacles remain to full Oneworld membership. "This shows that we are being taken seriously and that there is trust in us," Chief Executive Andre Dose told a news conference, noting a strong U.S. partner was crucial to the fledgling carrier making money on the huge U.S. market. Code-sharing could start by mid-May once U.S. authorities approve, officials said. Dose added that the deal with American was a first step to full membership of Oneworld, whose members he said have agreed in principle to take Swiss into the group. Marketing head Arjen Pen said Swiss aimed to be a full member of Oneworld -- led by American and British Airways Plc (BAY) -- in time for the winter flight schedule in six months. BA and Swiss would dominate routes between Britain and Switzerland and some rivals, such as EasyJet (EZJ), have already indicated they would ask the European Commission to force BA and Swiss to surrender landing slots at Heathrow airport if Swiss became a Oneworld member. Swiss had also talked to the SkyTeam alliance of Air France (AIRF) and Delta Air Lines Inc (DAL) and the Star Alliance of Lufthansa (LHAG) and UAL Corp's (UAL) United Airlines. BREAKEVEN SEEN IN 2003 Dose maintained Swiss's forecasts that it would lose some 1.1 billion Swiss francs this year on sales of 3.2 billion, although passenger traffic was running ahead of budget. Sales are set to rise to five billion in 2003, when Swiss aims to break even, compared to Crossair which lost 314 million in 2001 on sales of 1.06 billion. Crossair shares were trading down 0.5 percent at 50.25 francs at 1510 GMT. Swissair collapsed in early October after the drastic drop in passengers due to the September 11 attacks in the United States bowled over its already very stretched finances. In its wake, Belgium's Sabena [SAB.UL] went under as well because the Swiss minority owner could not provide funds. After a two-day grounding of the Swissair fleet which left thousands of passengers stranded, the Swiss government provided more than a billion francs to get the airline back in the sky until March 31. The state and Swiss companies coughed up 2.7 billion Swiss francs to mould Crossair and vital bits of Swissair into Swiss. Dose said Swiss could prosper when it takes off, aiming for high-end passengers willing to pay more than rock-bottom prices for leg room and good food and wine poured from full-sized bottles into real glasses, even in economy class. But he added he was concerned about the prospects for a U.S.-led attack on Iraq in Washington's "war on terror", which could hurt passenger volumes. Separately, Swiss said it planned to replace 13 Boeing (BA) MD-11 long-haul aircraft with Airbus A340-300 (EAD) jets for around $1.3 billion including spare parts. It said the Airbus had more seats, lower emissions and made far less noise. The decision means that Swiss will in a few years have an all-Embraer fleet for the short haul and various Airbus types for medium- and long-haul flights. Other members in Oneworld are Cathay Pacific (0293), Aer Lingus [AERL.UL], Iberia (IBLA), Finnair (FIA1S), LanChile (LAN) and Qantas (QAN). ©2002 Reuters Limited.