High oil price
The results just out are so good due to the fuel being hedged some time ago.
In effect the better off airlines buy most of the fuel a year ahead if the price is good. These hedges are running out and the current fuel price at over $900 a tonne makes new hedging less attractive. A year ago the airlines were paying around $650 a tonne for jet fuel.
The credit crunch is going to hurt the airlines this spring. Some people will cut back as the price of their home falls. A weekend break to italy will be the first thing to get cut.