NEW YORK (Bloomberg) — AMR Corp.'s American Airlines, once the world's largest carrier by traffic, may pursue alliances to win more passengers as rivals' mergers erase its former size advantage, analysts said.

Possible alliance partners include US Airways Group Inc. and JetBlue Airways Corp., the sixth- and seventh-biggest US airlines, said Jeff Straebler, a fixed-income strategist at RBS Securities Inc. in Stamford, Connecticut.

Alliances such as AMR's Oneworld let members sell seats on each other's jets, a benefit in an industry where the breadth of airlines' networks attracts corporate fliers. American, now the second-largest US carrier, would be No. 3 under the United Airlines-Continental Airlines Inc. merger announced yesterday.

"American helped originate the whole idea of alliances and partnerships," said George Van Horn, an analyst at business researcher IBISWorld Inc. in Los Angeles. "If somebody should be good at it, you could make the argument they should be."

Straebler and Van Horn said an alliance might be attractive to AMR by providing many of the benefits of a merger, such as adding passenger revenue and avoiding duplication of flights, without the risks and expense of meshing different fleets and unions. Ties to US Airways or JetBlue might help American in New York, the world's busiest travel market, they said.

AMR was under pressure even before the United-Continental deal emerged.

The Fort Worth, Texas-based company is the only major US airline that may lose money in 2010, and has the lowest margins and highest costs among its peers, according to Jamie Baker, a JPMorgan Chase & Co. analyst in New York. American and unions representing about 77 percent of its workforce are in contract talks, with the pilots' negotiations dating to 2006.

AMR fell 14 percent since April 7, when talks between United and US Airways were reported, through April 30 for the second-biggest drop among the 12 carriers in the Bloomberg US Airlines Index, behind Delta Air Lines Inc. United parent UAL Corp. and Continental led with gains of 14 percent and nine percent.

AMR rose 21 cents, or 2.9 percent, to $7.59 at 9:45 a.m. in New York Stock Exchange composite trading. The shares have climbed 45 percent in the past year.