I want a level 1 data flow diagram for online air ticket reservation system. I need it for my project. Thank you

airline booking system about data flow diagram

An airline reservation system (ARS) is part of the so-called passenger service systems (PSS), which are applications supporting the direct contact with the passenger.ARS eventually evolved into the computer reservations system (CRS). A computer reservation system is used for the reservations of a particular airline and interfaces with a global distribution system (GDS) which supports travel agencies and other distribution channels in making reservations for most major airlines in a single system.