Selon Google :
Rome Fiumicino
There are two train services between Fiumicino airport and the centre of
Rome: the FL1 and the Leonardo Express.
You can take a bike on the FL1 which stops at Tiburtina and
Trastevere station - of the two
Trastevere is probably the better option if you have a bike with you (
route map for the FL1 service
). A single ticket is 8 euros (plus you'll need a ticket for your bike). Unfortunately, the FL1 doesn't stop at Termini, the main rail hub, so if you are looking to take an onward train service then you may well need to change at
Trastevere and get a train into Termini (although from
Trastevere it's an easy cycle through
Rome's
centro storico to Termini station).
The
Leonardo Express
(
Leonardo Express timetable leaflet
) goes to and from the main Termini station and you
can't take a bike on it.