The National airline Alitalia operates flights between almost every major city and town in the country, and is a great way of getting around, although purists will use the train services, which are fast, comprehensive and comfortable on the inter-city routes, and stop almost everywhere on the rural ones.
Hiring a car is a pleasure in Italy, particularly because the roads are so good, with straight motorways following the ancient Roman Roads, which are pleasantly supplemented by twisty Alpine roads that go every which way but straight, and are an absolute joy to drive.