Perhaps the game is similar to the real World, in that the rising fuel costs will weed out the weak/poorly managed airlines. The main difference being that we had a pretty good idea this was coming and have had the opportunity to ensure that our growth was sustainable and that we have built up large enough cash reserves to ride through any potential problems that might arise. Those airlines who have spent massive amounts on ordering dozens of aircraft without really giving it much thought, are in my opinion the ones who will suffer most.
My airline (Japan National Airlines) is still producing very healthy profits despite the cost of fuel. Even though my fuel costs have risen substantially, I have not had to take any action to mitigate the situation. I have cash reserves equivalent to around 6-7 months of revenue sitting in the bank, just in case things take a turn for the worse.
It still surprises me how many airlines have very poor fleet commonality which must give them a pretty high cost base so as soon as other costs (eg. fuel) start going up, their profits are hit hard.
Just my two cents worth... good luck guys, it's just getting interesting