What is a booking class and how can I check it when booking a ticket?

When booking a flight in our booking service, you might notice a single letter, such as Y or J, written for each ticket. This letter indicates the class of service and the type of fare for the purchasable ticket. Together these make a booking class. 

Class of service is typically related to travel class (e.g. Premium Economy), while the type of the fare is about the ticket type (e.g. full-fare or campaign, Light or Classic). For example, Y is full-fare Economy Class while J is full-fare Business.