erDiagram

    AirlineCompany {
        AirlineID PK
        Name
        Address
        ContactPersonName
        TelephoneNumbers
    }

    Employee {
        EmployeeID PK
        Name
        Address
        BirthDay
        BirthMonth
        BirthYear
        Gender
        Position
        Qualifications
        AirlineID FK
    }

    Aircraft {
        AircraftID PK
        Capacity
        Model
        AirlineID FK
    }

    Route {
        RouteID PK
        Origin
        Destination
        Distance
        Classification
    }

    RouteAssignment {
        RouteAssignmentID PK
        AircraftID FK
        RouteID FK
        NumberOfPassengers
        PricePerPassenger
        DepartureDateTime
        ArrivalDateTime
        TravelTime
    }

    Crew {
        CrewID PK
        MajorPilot
        AssistantPilot
        Hostess1
        Hostess2
        AircraftID FK
    }

    Transaction {
        TransactionID PK
        Date
        Description
        Amount
        AirlineID FK
    }

    AirlineCompany ||--o{ Employee : "Has Many"
    AirlineCompany ||--o{ Aircraft : "Owns Many"
    AirlineCompany ||--o{ Transaction : "Has Many"
    Aircraft ||--|| Crew : "Has One"
    Aircraft }o--o{ RouteAssignment : "Assigned to Routes"
    Route }o--o{ RouteAssignment : "Assigned to Aircraft"