The country’s main airports are in Milan and Rome. Over the past few years, airlines like Norwegian and Turkish Air have run outrageous deals if you fly through their hubs so if you can find a short hop into Italy from Oslo or Istanbul, it may be well worth the discount. Also look for airlines like SAS, KLM, and Swiss.
Italy has a very well developed and fairly reliable rail system that will get you to most towns of note without much delay but the rise of budget airlines means that flying between cities can be just as cheap. But if you want to tour the countryside you’ll still need a rental car.