After a curse transformed former World War I pilot Marco Pagot into a pig, he took on the alias Porco Rosso, a well-known bounty hunter who chases sky pirates over the Adriatic Sea. Living on a secluded island, Porco ventures out mainly to collect bounties or visit Gina, a captivating singer who runs the Hotel Adriano.
On a trip to fix his faulty engine, Porco is ambushed by the ambitious young American pilot, Donald Curtis. Eager for recognition, Donald boasts that he will end the flying pig's career. To avoid disappointing Gina, Porco flees to the prestigious Piccolo S.P.A., an aircraft manufacturer, where he secures a substantial loan to refurbish and upgrade his fighter plane. Surprisingly, he finds that the company's lead engineer is Fio Piccolo, a 17-year-old aspiring aviation genius. With Fio's modifications, Porco is ready to confront Donald and restore his reputation.