Although some persons see it as a big bluff, Pan American World Airways has informed officials in New York that the giant international carrier is thinking of moving its corporate headquarters out of Manhattan.

Fantus Co., a corporate location firm that helped bring a major Mobil Corp. division to Fairfax County, has been hired by Pan Am and reportedly is studying such cities as Washington and Houston as a potential base for the airline.

A spokesman for the Metropolitan Washington Board of Trade said he was unaware of any Pan Am interst in the D.C. area but it is known that the company has been talking with local real estate people about new office space.

Behind Pan Am's expressed unhappiness with New York is an alleged lack of lobbying help for its route requests by members of the New York congressional delegation, according to Business Week magazine. The Texas delegation fought for Dallas-based Braniff International in a battle with Pan Am over authority for new service form Dallas-Ft. Worth to London and the Texans won.

The best guess is that Pan Am most of its 12,000 area womcers, complemented by New York City will remain in Manhattan with most of its 12,000 New York City new attention to Pan Am's needs by New Yorkers on Capitol Hill. At the same time, the airline firm is expected to expand its Washington offices.