I always favor train travel over air travel when it's convenient (and often faster). But when the train times hit about 3.5 to 4 hours, the time you save by being transported to a city center on the train evaporates--and taking the plane looks mighty good.
Our map below shows the major airports in Italy. Click a map marker and you'll find out more information about the airport, from a link to the official airport website, to how to get to the city via public transportation, to a price comparison for places to stay in or near the airport in case you're taking off in the early morning.
If you are arriving in Italy from the US, chances are you will be arriving at either Rome Fiumicino or Milan Malpensa. If you are leaving from Fiumicino, you might use the link above to check out the activities in the area around the town of Fiumicino on the coast.
When you're arriving from afar and are jet lagged, you might want to arrange an airport transfer in Advance.
To check on cheap flights to, from or within Italy, CheapoAir might help:
Ferries were once popular for getting to the islands, especially Sicily and Sardinia. This is becoming less common as Ferry fares have become a bit steep, especially for a family with a car. Today it's often better to fly and rent a car upon arrival, even if you have one at your disposal on the mainland--especially if you are only spending a short amount of time on the island. In the off-season, you'll probably find that taking your car with you on the ferry is a better deal. Check out our night ferry excursion to Sardinia.