PS - You may know that Ryanair features strongly in my book Strategic Management Dynamics for three reasons - its a simple business model, its well-known, and its data is almost entirely public. The case demonstrates cleraly the simple principles that [a] resources drive performance, [b] resources accumulate and [c] they depend on each other to grow.

The focus is very much on internal factors explaining performance. But of course external factors matter too - in this case the rising cost of fuel and the general fall in consumer spending.