ER Assumptions,

Having a login name and password when logging in.

The flight may have a unique number.

The flight schedule should be done by the admin.

An airline agency may have several phone numbers.

Having a passenger unique passenger number as well as a passport number.

A passenger may also have multiple telephone numbers.

There is also a seat number for each seat.

The airline must handle the flight as well as the passenger.

The agency should check payments.

It is mandatory to have a price for a ticket.


ER Explanation 

 The user is logged in. The user has a username, password, and email address. Each login is managed by an admin. Each login also has a login number, name, and password. The admin manages several logins and one login is managed by one admin. The admin uses a unique number, name, and password to identify you. The admin manages the airline agency and the agency may have a number, name and several phone numbers. An admin manages several airline agencies and only one admin manages one agency. The admin adjusts the flight and each flight has a number, DepatureAirport, DestinationAirport, DepatureTime, DepatureDate, ArrivalDate, ArrivalTime. The agency also handles the flight. One admin schedules several flights and only one admin schedule one flight.  The airline handles several flights, and one flight is handled by one agency. The agency handles the passenger. The passenger also stores a passenger number, first name, middle name and last name, address, date of birth, telephone number and passport number. The agency handles many and one passenger handles one agency. The passenger pays the ticket. The number, type and price are also stored on the ticket.  The passenger pays for one ticket and one passenger pays for one ticket. The ticket is checked by the agency. Tickets are checked by the agency and one ticket is checked by one agency. A seat is then booked for the passenger. The number and type of the seat are also stored. One seat is booked by the passenger and one seat is booked by one passenger.