Database schema consists of 4 tables:
Company table has ID and name of the company, which transports passengers.
Trip table has information about trips: trip number, company ID, plane type, departure city, arrival city, departure time, and arrival time.
The Passenger table has passenger's ID and passenger's name.
Pass_in_trip table has information about the flights: trip number, departure date (day), passenger's ID and his place during the flight. We should note that,