Flight
Sicily has 2 major airports: Catania and Palermo. Catania is the closest one to Milazzo (where the wedding venue is). If you are not planning to rent a car, the Catania Airport is also connected by train and bus to Milazzo.
Travel Note
Try to stick with reputable car rental companies: Alamo, Avis, Budget, Dollar, Europcar, Hertz, National, Sicily by Car, Sixt, Thrifty