As you suggested, flashmeister, profitability is a crucial part of how Wall Street values a company. After all, an individual (or fund manager) putting money into a company's shares is interested in return on investment. By way of example, TWA was producing around 2 billion RPM's/year in 2000, and yet their market capitalization (in a strong stock market, to boot) was well under $100 million. The reason was obvious: TWA was continually losing money and many investors and analysts felt that bankruptcy was not a question of "if," but "when." Since common shareholders are generally left with nothing even if a company reorganizes successfully, TWA's depressed share price reflected sentiment regarding the future value of its shares.
Similarly, investor sentiment regarding United, US Airways, and America West continue to depress their share prices. It's believed America West would have been forced to file for bankruptcy protection had they not received government loan guarantees; moreover, the terms under which the guarantees were granted will result in substantial (close to 50%) dilution of current shareholder equity. America West is also technically in default on some of its lease payments, as it will have failed to make the required payment within the grace period. US Airways just posted a pre-tax operating loss of $577 million for the quarter and a net loss of just under $2 billion for the year (including writing down the value of parked aircraft). US Airways was burning through cash at the rate of $7 million per day in the fourth quarter, but expects that to improve to a loss of "only" $3 million per day in the first quarter. Also recall that US Airways is highly leveraged. As for United...Wall Street is holding its collective breath, as the conventional wisdom held that UAL was losing $10-15 million per day in the fourth quarter.
American, Delta, Northwest, and Continental have seen their market capitalizations hold up better because it's believed they're all reasonably well-positioned to emerge intact from the airline industry crisis. While Northwest has substantial debt, it also has a large cash cushion and, though its fleet is one of the oldest in the industry, it owns its planes. And Northwest managed to post a profit in Q3. Continental is in good shape (though it too is highly leveraged) because its cost structure is lower, its yields are improving, and it is likely to be the first network major to post a profit in 2002. Both American and Delta have a large number of unencumbered aircraft, substantial cash reserves, and cost advantages over UAL and US Airways.
As for the market cap king, Southwest, the reasons are even more obvious today. Southwest posted a PROFIT for the 4th Quarter. Not just a profit including the government subsidy, but an operating profit. They have virtually no debt, a young fleet of mostly owned aircraft, and a cost advantage over all their competitors. They were not forced to reduce capacity and, in fact, will be adding flights in February. Southwest is well-positioned to take advantage of its competitors' weaknesses and continue to grow market share. United discontinued United Shuttle. US Airways shuttered Metrojet. Delta cut Delta Express in half. Southwest's market cap reflects investor sentiment regarding its future growth and profitability.