They hedged fuel to reduce risk. Had they not hedged they would have been speculating that the fuel price would go down, which is riskier than hedging. Once they purchased the options for fuel at a particular price they became indifferent to the movement of the market, at least as indifferent as one can be at $140/barrel anyway.
Now that the price of fuel dropped dramatically we can see that they have lost money on the value of their options however this is probably outweighed by the profits they will realize from the lower cost commodity. A lot of people say company X lost Y dollars from fuel hedging -- well, it is not really an accurate comparisan unless you also account for the amount of money they made from low fuel prices.