Nov. 7 (Bloomberg) -- Delta Air Lines Inc. is hiring Dentsu Inc. to lobby Japanese politicians on its proposed tie-up with Japan Airlines Corp. after former adviser Fleishman Hillard Inc. withdrew, three people familiar with the situation said.

Fleishman stopped work on the project because it also represents carriers in Oneworld, a rival grouping to Delta’s SkyTeam, said the people, who declined to be identified because the talks are private. Shin Tanaka, a Fleishman spokesman, said Delta is not a client.

Delta has begun efforts to lure JAL, Asia’s biggest carrier by sales, into its alliance as the Japanese carrier seeks government support and new investment to avoid collapse. American Airlines is leading efforts to keep JAL in Oneworld, including having held talks on buying a stake.

A spokesman for Dentsu, Japan’s largest advertising agency, declined to comment, saying the company doesn’t speak about specific clients. Hiroko Tanaka, a spokeswoman for Delta in Tokyo, also declined to comment.

Delta and American are seeking deals with JAL because of its networks in Japan, the world’s second-largest economy, and China, Asia’s biggest air traffic market. Delta flies passengers from nine U.S. airports year-round to Japan, including New York, San Francisco and Honolulu, while American Airlines has four U.S.-Japan routes.

American, Delta Battle

Fort Worth, Texas-based AMR Corp.’s American Airlines has urged JAL to seek antitrust immunity to collaborate on schedules and pricing as soon as a U.S.-Japan “open skies” aviation treaty is concluded.

Delta, the world’s biggest carrier, is running full-page newspaper advertisements in Japan this week to promote the company. The carrier became the biggest overseas airline at Tokyo’s Narita airport last year after buying Northwest Airlines Corp.

Fleishman is a unit of New York-based Omnicom Group Inc., the world’s second-largest owner of advertising agencies.

JAL fell 1.8 percent to 109 yen in Tokyo trading yesterday. The stock has slumped 49 percent this year, the biggest decliner in the Nikkei 225 Stock Average.

Dentsu, which was formed in 1901, has some 6,500 employees. The company has more than 40 subsidiaries in Japan, and more than 60 units in the U.S., Europe, the Middle East and Asia.

To contact the reporter on this story: Chris Cooper in Tokyo at ccooper1@bloomberg.net; Takahiko Hyuga in Tokyo at thyuga@bloomberg.net

Last Updated: November 6, 2009 10:00 EST