China's national airline announced today that it had agreed with Taiwan's airline to begin unprecedented direct negotiations Saturday on the return to Taiwan of a cargo plane and two crew members.

The negotiations, to be conducted in Hong Kong, will be the first known government-authorized contacts in nearly four decades to be held between the Communist Chinese and their Nationalist foes on Taiwan.

For Peking, much more will be involved than the Boeing 747 jet, its cargo and two crew members who want to return to Taiwan after being stranded on the mainland when the pilot flew the plane to China and defected. Diplomats here say that Peking will try to use the negotiations to promote further contacts between the two sides as well as movement toward the ultimate goal of reunification between Taiwan and the mainland.

For Taiwan, diplomats say, the aim will be to try to get the plane and the two crew members back with a minimum of contact.

"One side will try to prolong the contact, and the other will try to minimize it," a diplomat said. "For Taiwan, the less negotiation, the better."

Diplomats said that while airline representatives will be doing the talking in Hong Kong, the real decisions on strategy and tactics will come from top leaders in Peking and Taipei. The agreement to hold the Hong Kong talks between the two sides is seen in Peking as the biggest development to occur in the relations between the two sides in many years.

The announcement that the foes would meet on Saturday was made by Zhang Ruipu, manager of the Hong Kong office of China's national airline. Zhang said three representatives from China's airline, the Civil Aviation Administration of China, including himself, would meet with three representatives from Taiwan's national carrier, China Airlines.

In an attempt to avoid direct contact with representatives from the mainland, Taiwan had originally proposed that the Hong Kong-based Cathay Pacific Airways, which flies to Taiwan and to China, act as its agent in the negotiations with Peking. China rejected that proposal but agreed to hold the talks away from Peking.

Taiwan's agreement to hold talks in Hong Kong, announced Tuesday, seemed to take the Communist Chinese by surprise.

Until now, Taiwan has insisted on a "three no's" policy of no contact, no compromise and no negotiations with Peking. In agreeing to meet with representatives from China's airline, Taiwan said it would merely be a matter of "business type" talks between two civil airlines.

Taiwan maintains that the Communist government in Peking is a rebel group with which it cannot deal. Peking regards Taiwan as breakaway province. For several years, however, China has been offering the island a reunification plan under which Taiwan would retain its own Army and system of government.

The drama began when Taiwanese pilot Wang Xijue flew the Boeing 747 to an airport near the southern Chinese city of Guangzhou and said he wanted to be united with his family members on the mainland, including his 82-year-old father and three brothers. He left a wife and two children in Taiwan. In the past, most defections have been from China to Taiwan.

Some observers here said the warm, well-organized, high-level reception that Wang received within hours of his arrival in Guangzhou may have been an indication that the pilot's defection was somehow arranged well in advance of his flight to the mainland.

At a press conference in Peking on May 7, Wang denied he had received any monetary award for his defection.