I can only tell you from what I know in the past. Other airlines are adding additional costs like charging for the first bag, or second bag, when most of them didn't in the past. Southwest is still not charging for the first two bags, as of the time of this post,they said they are not going to. I haven't seen Southwest do anything drastic in relation to their fees since 9/11, however, I am not sure when they will be negotiating their next gas purchase. I think the gas prices are hurting everyone, everywhere. I know some airlines are retiring their larger planes in their fleets, and cancelling flights to try and save on gas. I haven't heard of anything like this through Southwest, all planes are the same size, type. But that doesn't mean it can't or won't happen. They just haven't announced anything. Honestly, I don't have any information other than being married to someone who works there. But knowing the company from an employee side, I believe that Southwest is a great company and that they won't do anything major with out thinking of how it is going to affect their customers. I think they are sitting back and watching how these other changes from other airlines are affecting them business wise. You may see other airlines going up 50.00 a ticket, but Southwest may go up 5.00 or 10.00. They don't gouge you. I asked my husband if it would be safe for me to tell you to buy your tickets when you want them, and not when you feel like you have to. And he said, yes, that is a good thing to say because if Southwest raises their fees, it would only be that 5 or 10 bucks. Southwest prides itself on being a lowcost carrier who, right now, is in a great position with the choices that its CEO and others up there have made.
He also said that with American charging for that first bag, other airlines are going to sit back and see how that goes. Are flyers going to be willing to pay for their one checked bag to be flown, or are they going to stay away from American and go to other companies? I think if American doesn't get too much heat for it, and their loyal customers will pay it, then more airlines will start charging that as well because it is another way to make a profit where they haven't been making it before. They have skimped on everything they can up until now. Airlines are stuck between trying to stay in the air and still making flying affordable.
So as far as Southwest and their prices, I wouldn't get in a hurry just based on fuel prices. My husband said that Southwest is locked in on 80% of their gas for the rest of the year. So the gas prices can go up and it shouldn't directly affect Southwest. I would just buy your tickets when you see a sale or can afford to. They are usually pretty consistant.