American Airlines and other oneworld alliance partners said Tuesday that ailing Japan Airlines Corp. would make $2 billion in commercial benefits in the next three years if it stays in the fold.

American and U.S.-based private-equity firm TPG Inc. also raised their investment offer to $1.4 billion, up from 1.1 billion.

"This proposal demonstrates oneworld's extraordinary commitment to JAL," said Tom Horton, executive vice president of finance and planning and CFO of AMR Corp., American's parent company.