The CEO said, one class, one price. Need I create a 'Class' class? 'Class' should link to 'Seat'(one to one), right? Should the 'Class' link to 'Equipment'(multiple to one)? or 'Class' link to 'Flight'(multiple to one)?
Instead of having a separate class named 'Class' you can have one attribute called 'type' which represetns whether the seat belongs to first class or coach.