EXT and PMI are unique codes to identify airports used in the aviation industry. They are defined by IATA (International Air Transport Association) and are commonly called IATA codes. EXT to PMI refers to a flight route from Exeter Airport to Palma de Mallorca Son Sant Joan Airport. Ibiza Airport (IBZ), Menorca/Mahon Airport (MAH) are some additional IATA codes for airports related to your trip.