Ryanair are brilliant at wrong footing the competition and excel in a pricing war since they have always had the lowest operating cost of any European airline which is why they are now the largest European airline.
In order to hit their passenger targets at Stansted they are driving down prices again. Their stated goal is to ultimately offer free flights but to earn their revenue from ancillaries such as retailers, luggage, car rental, food etc.
No different to the mobile phone industry that gives away phones in exchange for airtime contracts or YouTube that gives away content in exchange for advertising revenues.
Not a bad model!