Pan American has quietly formed - and sold out - what is believed to be the first commercially sponsored American air tour of the People's Republic to China for ordinary travelers. Prior to this, virtually the only way an American tourist who did not belong to a special interest group could go to China was a member of a group organized by a foreign carrier, or as a passenger on a round-the-world cruise. The one big exception has been Chinese-Ameicans.

Part of Pan Am's agreement with Chinese officials called for no publicity about the tour, so no public announcement was made. Instead, on Sept. 10 the airline sent brochures to its best customers, inviting them to sign up for a 16-day trip starting Dec. 1 to Canton, hangchow, Shanghai and Peking. In four days 120 passenger made reservations at $2,400 a head, and the waiting list was closed at 800.

Passage depends upon the ability to get a visa, and the Chinese have indicated that no journalists, person with relatives or friends in the People's Republic, or sick or elderly persons will be admitted. The itinerary includes tourist attractions as well as visits to industrial sites.

Though Pan Am representatives will accompany the tourists in China, internal travel will be on Chinese lines. Pan Am will fly only as far as Hong Kong.