In Porco Rosso, what is the name of the American pilot who challenges Porco?

In Porco Rosso, the American pilot who challenges Porco is Donald Curtis.

Curtis is a brash American ace hired by the airborne pirates to defeat Porco, an Italian former World War I fighter pilot who now works as a bounty hunter over the Adriatic Sea. Curtis flies a Curtiss R3C seaplane, linking him to the real American aviation pioneer Glenn Curtiss.

After Curtis shoots down Porco's red seaplane, Porco has it rebuilt in Milan with help from the young engineer Fio Piccolo. Their rivalry culminates in a duel arranged after Curtis and the pirates ambush Porco. Fio adds a humorous condition: the winner's terms determine whether Curtis must pay Piccolo's debts or may marry her.

A common mix-up is Porco's real name, Marco Pagot, which belongs to the protagonist rather than his American rival. The film's antagonist is called Donald Curtiss in some discussions, while the film commonly uses Donald Curtis; the stored answer matches the standard English film naming.