Why do I need 50 from Fengtai District to Daxing airport metro?
Because the Beijing Metro Airport Line (including the Capital Airport Line and Daxing Airport Line) is charged separately and will not be merged with other lines.
The fare for the whole journey of Daxing Airport Line (Caoqiao Station to Daxing Airport Station) is 35 yuan Money (commercial vehicle 50 yuan), and the fare for the subway from Fengtai District to Caoqiao Station is 50 yuan Money.