To travel on the FL1 regional train or Cotral services, you can purchase a Metrebus Lazio ticket valid for zones A (Rome) and B (zone A counts as 2 zones + B, for a total of 3 zones). Alternatively, you can purchase the airport-to-Rome journey separately and, once you arrive in the city, use a Metrebus Roma ticket. The Leonardo Express, on the other hand, requires a dedicated ticket and is not included in Metrebus Lazio integrated tickets.