Your points are basically irrelevant towards the cost discussion, and for the most part, incorrect. I will explain why.
First of all, my point was that an airlines largest expense is emplyee wages, and it is here that low fare airlines gain the largest advantage. You responded by pointing out some other areas which, from the tone of your post, you think are more significant than salaries. You are mistaken, and I will show you why, using comparisons between Delta and airtran. However, you can use just about any major and any low-cost airline, and get similar numbers. These numbers come from the annual reports. It is public information, and easy to obtain. You might want to read them a little before your next post.
You mentioned that airtran saves money because of a fuel-efficient fleet. While I grant you that the 717 is a cool airplane, it does not quite give you a cost advantage on fuel. In 2001, delta hedged fuel, and as a result, spent an average of 68.6 cents per gallon. Airtran, on the other hand, spent 93.85 cents per gallon. Fuel made up 11.7% of Delta's total expenses, while fuel made up 22.14% of airtran's. As you see, airtran does not have a cost advatage because of fuel. As a matter of fact, Delta does.
You also mentioned that the fact that airtran bought inexpensive airplanes gave them a financial and cost advantage over Delta. First of all, that is not necessarily true due to higher maintanence costs of older airplanes. Secondly, no matter how cheap the airplanes are, airtran leveraged themselves very heavily to get them. As a result, their debt to equity ratio is 7.91 (ouch). Delta's is 2.77 (not to good either, but a lot better than 7.91). As a result, airtran does not enjoy a cost advantage on interest payments, either, as you assert. Delta has a cost advantage here, too.
You speak of a high percentage of passengers booking through FL's website. That is correct, and you are correct that that does save money. Not as much as you think, however. They still have to pay high CRS (computer reservation fees), and Delta has significantly cut TA commissions. Also, we are selling a lot through Delta.com. Not as much as FL, but we are catching up. As a matter of fact, when you add advertising costs to distribution costs (what I believe represents to total cost of selling a ticket), you will find that both airlines spend roughly 7% of total expenses. Not much of a cost saving here.
I will grant you that there are other cost saving factors, but none are enormously significant.
So how does airtran and others enjoy such a huge cost advantage? Well, I go back to my original statement, for which I took so much heat. They pay their employees less. In 2001, employee salaries and related costs made up 39.56% of Delta's total expenses. At airtran, only 25.27% of total expenses were spent on employees. It is is a difference, and it is significant. I will say it again, salaries are an airlines largest cost (by far), and low fare airlines pay much less in salary than the majors do. It is for this reason that they have such a cost advantage, and for this reason that they are able to offer such low fares. To assume otherwise is naive.
That is why I started posting on this topic in the first place. While the consumers love the low fares, I thought more people should know just how these airlines can afford to offer them. Most won't care. Some will.
That being said, Critter, I would advise you to tone down your responses a bit. I have yet to start the "trash talk" ( I can and will if I have to), I don't think that I am "making a fool of myself," and I certainly think that I have done my homework. The airline industry is very interesting to me, it is how I make my living, and I have done a lot of reading on the subject. I still have a lot to learn, but I do consider myself somewhat knowledgeable regarding the airlines and their finances.
I would suggest that it is you who need to do some homework.