エアラインにも情報があります

WizzAirのサイトにも、

Rome Ciampino airport to Rome Termini station
Terravision, our airport transfers partner, runs a direct, non-stop coach service between Rome Ciampino Airport and Termini Station, in Rome’s city centre, with high departure frequency scheduled around flight arrival and departure times. Tickets cost only €8 (one way) and €14 (return), and journey time is approximately 40 minutes. Plan ahead and BOOK NOW.

というのがあり、ここから予約が可能です。

利用する空港とエアラインは情報の最大の宝庫です。