Negotiators have initiated the first air agreement between the United States and the People's Republic of china, opening the way for the first regualr flights between the two countries since 1949.

Chief U.S. negotiator Boyd Hight declined to give details of the agreement pending its approval by an interagency committee in Washington. But sources close to the talks said it sharply diverged from U.S. practice by allowing only one American airplane to participate in the first two years of operations.

The agreement was initialed by Hight and Lin Zheng, deputy general director of the Civil Avaition Administratioin of China, at a ceremony in the Peking Hotel. Some sources indicated flights might begin as early as October, although Hight declined to give a date.

According to a source close to the talks, the agreement provides for one U.S. flight and one Chinese flight each week.

A source close to the talks said the air agreement calls for the Civil Avaition Administration of China (CC), Peking's state airline, and one U.S. airline to share a route betweenthe American cities of San Fransisco, New York and Honolulu and the Chinese cities of Peking and Shanghai with a stop in Tokyo. It incidated negotiations would begin for another route for a second U.S. carrier, but if unsuccessful after two years the second carrier could join the primary route.

Two airplines, Pan American and Nortwest Orient, are expected to be first in line for participation in the route. Both served China when service was cut off here in 1949, the last year the Communist came to power.

The Civil Aeronautics Board recommends a carrier, but the president must make the final decision.

Business sources here said that since an Aug. 25 request by the CAB for applications for the China route, at least seven airlines have applied.