San Francisco is threatening legal action against Oakland International Airport’s operators if they do not drop plans to include the words San Francisco in the potential renaming of the East Bay aviation hub. San Francisco City Attorney David Chiu sent a letter Monday to the Oakland Board of Port Commissioners demanding that they scrap a proposal to rename the airport “San Francisco Bay Oakland International Airport.” The Port of Oakland operates the airport. “In addition to the immense confusion and chaos the renaming would cause for travelers and consumers generally, this proposal also infringes on SFO’s trademark,” Chiu said in a statement. SFO Airport Director Ivar C. Satero said the airport supports a legal challenge, if necessary. “I urge the Port of Oakland not to proceed with this proposal and hope they will work to find a solution that provides clarity, not confusion, for the travelers visiting the Bay Area,’’ Satero said in a statement. The naming tug-of-war is raising friction between two of the Bay Area’s three major airports — neither of which are located in San Francisco. San Francisco International Airport — owned and operated by the city and county of San Francisco — is on the bay in San Mateo County, nestled next to the cities of San Bruno and Millbrae. A poll conducted by Oakland’s FM3 Research last summer shows that 27% of respondents in Alameda and Contra Costa counties said they were “very comfortable” with a name change. The number was slightly higher for those polled in Oakland. The poll data is the result of about 1,400 online interviews with registered voters conducted between May and August. The surveys also showed that 64% of respondents said it is either “extremely important” or “very important” to expand Oakland airport’s flight offerings, and are comfortable with a name change as part of that effort. But San Francisco city officials said the renaming plan appears intentionally designed to divert travelers who may be unfamiliar with Bay Area geography and lead them to believe the Oakland airport has a business relationship with SFO, which it does not. Officials said the proposed renaming would be particularly challenging for international travelers who may not speak or read English—an “important segment of SFO’s customer base.” The Port of Oakland said in a statement Monday that “the proposed name modification will clarify, not confuse.’’ “The new name identifies where (the Oakland airport) is actually located, which is on the San Francisco Bay. If the proposed name modification is approved by the Board, the Port will take all appropriate measures to defend its right to use this accurate geographic identifier,’’ the statement said. The possible name change is part of a broader effort by the Oakland airport to attract more domestic and international flights, improve the passenger experience at the aviation complex, including an upgrade of the Terminal 1 check-in lobby, and the addition of new concessions and restaurants. The Port of Oakland Commission is slated to consider the name change at a meeting at 3:30 p.m. Thursday. The airport will retain its aviation code of OAK, regardless of the fate of the proposed name change.