Travelers can upgrade their Swiss Air flight to first class 24 hours before departure for all long-haul flights by paying a fixed price and using miles and points on the official website and app. Moreover, to upgrade their flight in SWISS First Class, travelers can bid for an upgrade, ask to upgrade at the check-in counter or at the gate on the day of departure, use miles & card points for an upgrade at booking time, etc. To know more about the cost, booking process, and facilities, travelers can visit the official website or read the blog mentioned by Fares First Class.