Pantelleria's small airport, on the north-west coast just south of the town, has year-round flights from Trapani and Palermo (around 40 minutes), and seasonal connections from Milan, Rome, Venice and Catania in summer. Tickets are cheap if booked early and surprisingly expensive at the last minute in August.
The Siremar overnight ferry runs from Trapani daily in summer and three or four times a week the rest of the year, taking about five and a half hours. It is the cheaper option, and if you bring a car you'll have far more freedom on the island than on a rental. The harbour is right in the centre of Pantelleria town.