A major project planned to make transit between Italy’s major airports started in December 2014 when the first two airports got connected directly by a high speed rail line, Rome’s Fiumicino and Venice Mestre.
The line currently operating between Rome and Venice travels directly between Fiumicino Airport and Venice Mestre both ways. There are designated stops along the way: Rome Stops: Roma Termini, Roma Tiburtina, Florence: Firenze Santa Maria Novella, Bologna: Bologna Centrale, Padua: Padova and Venice: Venezia Mestre. The efficiency will no doubt increase flow of visitors to 2nd and 3rd tier cities. Check in for airlines should be available at the Airport of departure for the destination airport.
The high speed train being used is the Frecciargento, it is not the fastest high speed in the Trenitalia network, but it is quite fast. The private owned company Italo which has been making a move in the market is expected to deliver some competition for the routes soon. One example of a Rome Venice fare on this high speed line recently was 60 Euros but prices may vary. Train and Flight combination tickets are also projected to be available.
The trains departing Fiumicino leave at 11:08 and 15:08, and in the opposite direction depart from Venice at 05:40 and 09:25. From Rome it will take 2 hours and 14 minutes to reach Florence, 2 hours and 59 minutes to reach Bologna, 3 hours and 57 minutes to reach Padua and 4 hours and 12 minutes to get to Venice Mestre.