Delta Air Lines , the world's biggest carrier, is in talks to invest in struggling Japan Airlines Corp (JAL) <9205.T> and become its top shareholder, Japanese media said on Friday.

Public broadcaster NHK and Kyodo news said Delta was in talks to invest several tens of billions of yen (several hundred million dollars) in JAL, Asia's largest airline by revenue, as part of a business alliance.

I can't verify what has been reported by NHK and can't comment further at this time, said a JAL spokeswoman.

JAL is headed for its second straight loss this business year and is restructuring under state supervision after receiving a 100 billion yen credit line backed by the government.

JAL and Delta are also talking about code-sharing on international flights, Kyodo and NHK said.

JAL reported a 50.9 billion yen operating loss for the year to March 2009 and has forecast a 59 billion yen loss for the current year, as it struggles to control costs and suffers along with other airlines due to a slump in global travel.

Delta became the world's leading airline when it acquired Northwest Airlines in October.

(editing by John Stonestreet)