What does the ticket price consists off?
The ticket price normally contains three components: The airfare, tax & levies and the service fee. Low cost carriers sometimes add credit card and luggage charges.
Airfare
The actual price for the product “flight” which is calculated by the airline.
Tax and airport levies
Tax and levies is a collective sum of costs which are added to the actual ticket price which may even contain some additional surcharges. General rule: Tax and levies are costs which the airline aquires for 3rd persons (airport, government). Note the kerosene surcharge is an internal cost factor of the airline.
Service fee
The service flat rate has been introduced by Lufthansa on the 1. September 2004 and is presently used by most airlines. It contains costs of issuing and conveying the ticket, in other words the service regarding the ticket.
Credit card and luggage charges
Most low cost carriers (e.g. Ryanair or Easyjet) charge extra for bookings by credit card. Some low cost carriers also charge from the first luggage piece (e.g. Ryanair) but most carriers allow up to 20 kg free of charge.