American Airlines may team with private-equity firm TPG Inc. to invest at least $300 million in alliance partner Japan Airlines Corp., a source familiar with the plan said.

That sum would be competitive with a proposed investment in JAL by Delta Air Lines Inc., said the source, who declined to be identified because the talks aren't public. Delta, a member of the SkyTeam group of airlines, wants to lure money-losing JAL from American's oneworld group.

TPG would bring experience in working with troubled carriers, including helping return bankrupt Continental Airlines Inc. to profit in the early 1990s. JAL is due to receive bridge loans from the Development Bank of Japan while a government-affiliated fund considers providing financial assistance.

"This is a marriage that may work," said Jay Sorensen, president of consultant IdeaWorks. American "has a clearly proven track record for international operations and knows its way around an alliance, and then you have people who are going to provide the financing."

JAL is seeking government support and new investors as it heads for a fourth annual loss in the past five years. American and Delta want access to JAL's route network in Japan and China, Asia's biggest air-traffic market.

"TPG could potentially help," American Chief Financial Officer Tom Horton said Wednesday in Tokyo as he announced the partnership. He didn't say how big the potential investment would be.

TPG would seek an equity stake in JAL in exchange for a cash infusion, said a another person familiar with the talks. The firm needs approval from the Japanese government to take a formal role in any negotiations, this person said.

Jochen Legewie, a spokesman for TPG, and Charley Wilson, a spokesman for American, declined comment. TPG and American are both based in Fort Worth, Texas.

JAL has applied for funding from Enterprise Turnaround Initiative Corp. of Japan as it restructures operations. A decision won't be made until next year, according to JAL.

A person familiar with Delta's JAL talks said in September that any investment by the Atlanta-based carrier would be at least several hundred million dollars. A spokeswoman, Betsy Talton, declined comment Thursday.

American parent AMR has completed about $5 billion in financing and liquidity accords since July, and could use some of that money for a JAL infusion. AMR said Oct. 21 it has $1.1 billion in long-term debt and capital leases that mature in 2010 and a minimum $525 million cash pension expense.

"If they're going to get into a bidding war with Delta over a stake in JAL, it's going to be difficult for them to compete unless they have outside help," said Hunter Keay, a Stifel Nicolaus & Co. analyst who rates AMR as "hold."

Oneworld, SkyTeam and Star Alliance, the three main global airline groups, help carriers cut operating costs and allow them to expand sales networks without the difficulties or expense of a merger. JAL gets as much as $500 million a year in additional revenue from its oneworld partnerships.

TPG, formerly known as Texas Pacific Group, has invested in carriers including Midwest Air Group Inc., America West Holdings Corp., Tiger Airways Pte. and Ryanair Holdings PLC, in addition to Continental. It was founded by David Bonderman, chairman of Dublin-based Ryanair. TPG backed a failed takeover bid for Australia's Qantas Airways Ltd., a oneworld member, in 2007.

"TPG knows the airline business quite well," said Robert Mann, president of aviation consulting firm R.W. Mann & Co. "They clearly are very capable and smart individuals."

Delta Chief Executive Officer Richard Anderson said last week that the carrier is working with SkyTeam on recruiting JAL as a member. The U.S. airline has offered to reimburse JAL for sales lost during any move to the group, the Wall Street Journal said, citing an unidentified source.