Lawsuits are flying in a dispute between two California airports over the right to use the name "San Francisco" -- despite neither of them being in the city.

San Francisco International Airport (SFO) is suing the recently renamed San Francisco Bay Oakland International Airport (OAK), insisting the similar sounding names might confuse potential passengers.

Their lawsuit has been met with a counterclaim from The Port of Oakland asking a judge to rule its airport's new moniker -- which replaced "Metropolitan Oakland International Airport" -- is not a copyright infringement.

"Changing 'Metropolitan' to 'San Francisco Bay' in Oakland Airport's name accurately describes OAK's geographic location on the Bay and presents the airport as an additional choice for travel into the San Francisco Bay Area," said port attorney Mary Richardson on Thursday, announcing the lawsuit.

The San Francisco city attorney's decision to pursue litigation "is an attempt to stop consumer education, prevent expanded air travel options for Bay Area residents and visitors, and is a misguided use of San Francisco taxpayer dollars," she added.

The legal turbulence began in April when officials in San Francisco sued for copyright infringement, claiming the name change was a customer grab and an effort to poach business.

"The Metropolitan Oakland International Airport seeks to increase passengers and profits by rushing to unlawfully incorporate San Francisco International Airport's trademarked name into its own," the suit says.

Passengers could easily mix up the two destinations, the suit says, and end up stranded.

"The potential for confusion will be particularly acute for international travelers who may not speak or read English," it says.

"Travelers will very likely be confused and book tickets to the unintended airport, thinking that the 'San Francisco Bay Oakland International Airport' is SFO and arrive in the wrong place, a mistake leading to missed flights and connections, among other problems."

Despite the lawsuit, officials in Oakland voted unanimously to adopt the new name on Thursday, in a move that will not affect the "OAK" designation used on baggage tags.

The two airports sit just 10 miles (16 kilometers) apart, on opposite sides of San Francisco Bay.

Neither of them is actually in San Francisco -- SFO is in San Mateo County while OAK is in Oakland.

Both airports are a 20-40 minute taxi ride to downtown San Francisco.