Cross-bay rivals Oakland and San Francisco are entering a new era of bickering.

For decades, the competition between the “city by the bay” and its more down-to-earth neighbor centered on the region’s dueling professional football and Major League Baseball franchises. But with the Raiders fleeing Oakland and the Athletics poised to follow suit, the two cities apparently needed something new to quarrel over.

Cue the airports.

San Francisco on Tuesday asked a federal judge for a preliminary injunction to prohibit the airport in Oakland from using its newly chosen and all-encompassing moniker, the San Francisco Bay Oakland International Airport. Notwithstanding the new name, the East Bay airport maintains its same OAK airport code and the “I Fly OAK” logo, and its runways continue to hug the east side of the San Francisco Bay.

San Francisco alleges in court filings that the airport’s new name amounts to trademark infringement, is confusing for travelers and is an ill-concealed attempt to attract San Francisco International Airport’s customers.

“Although the Oakland airport services many of the same Bay Area travelers as SFO, it receives far fewer of them,” attorneys for San Francisco wrote in the court document. “What better way to attract new customers, service providers, and airlines than by adopting a copycat brand?”

Port of Oakland clapped back in a news release this week saying that San Francisco is simply trying to “erase OAK from the map.”

“This is not and has never been about SFO or confusion,” Mary Richardson, attorney for the Port of Oakland, said in a statement. “It’s about bringing awareness to travelers about the choices they have when traveling to and from the nine-county San Francisco Bay Area.”

The fight began in the spring after the Board of Commissioners for the Port of Oakland voted to change Oakland International Airport’s name to the more inclusive San Francisco Bay Oakland International Airport.

Port Commissioners President Barbara Leslie said at the time that the move was an effort to help travelers better understand the airport’s location. The airport in Oakland, which opened in September 1927, is famously known as the place where Amelia Earhart took off on her ill-fated attempt to fly around the world.

But San Francisco International Airport, which has operated since May 1927, immediately came out against the name change, arguing that it would cause confusion. Days after the Oakland Board of Port Commissioners voted for the new name in April, the city of San Francisco filed suit in federal court.

San Francisco City Atty. David Chiu said in a statement this week that the airport’s branding update has caused travelers to book flights to San Francisco International Airport intending to travel to Oakland. Others have been directed to the wrong airport by digital assistants and rideshare services.

Attempts to talk to Oakland officials to come up with alternative names were not successful, Chiu said.

“San Francisco has invested millions in making San Francisco International Airport the world class airport it is today. We have built an incredible brand that we must protect,” he said. “Oakland has a trademark for Oakland International Airport. It should use that and stay away from San Francisco’s brand.”

In her statement, Richardson accused San Francisco of attempting to stifle competition and position SFO as the only airport serving the Bay Area. “It is not, and OAK will continue to aggressively fight for its position on the San Francisco Bay.”