Personnel are important to the airline. The different classes of employee include pilot, flight attendant and security agent. Each person hired has a unique SSN, a start date, and a name. The system should also track their current salary. In the case of pilots, it must track their total number of flight hours and the number of years flying experience they have had.
Flight attendants are qualified to work in certain models of plane.
In addition, pilots are certified only to fly certain models of plane. Certification for each class of plane needs to be renewed on a regular basis, so the system must be able to generate a reminder when certification is due to expire. The airline has a number of different flight numbers. Each flight number goes between two airports. It runs at the same time every day.