By THE STAR STAFF The Puerto Rico Ports Authority (PRPA) is filing multiple notices of intent (NOIs) with the Federal Aviation Administration (FAA) to impose and use passenger facility charges (PFCs) to fund infrastructure projects in several airports.   PFCs in Puerto Rico vary by airport, but major commercial hubs currently charge the federal maximum of $4.50 per flight segment, according to the FAA. The fees are integrated into the airline ticket price and used for airport improvements...