Consider the following attributes of

FlightN $,$ FromCity, ToCity, FlightDate, DepartureTime, ArrivalTime, TicketN, TicketDate, PassengerName, Cost,Completed, PassengerAddress, Passenger Age.

Based on the following assumptions:

$-$ FlightN is the key for FromCity, ToCity, FlightDate, DepartureTime, and ArrivalTime;

$-$ Every ticket belongs to only one passenger;

$-$ Every passenger may purchase more than one ticket;

$-$ Every Ticket may include more than one flight;

$-$ PassengerName is the key of PassengerAddress and PassegerAge;

$-$ Every flight of a ticket together determine the Cost and the attribute

$-$ Attribute 'Completed' indicates whether the flight has been completed $($ i$.$e$.$ the passenger has taken the flight$).$