A little over 10 years ago, there were a dozen major domestic airlines. Following a wave of bankruptcies, the industry consolidated, and today four remain—American, Delta, United and Southwest.The Investor Alert is U.S. Global Investors' weekly newsletter featuring a brief, in-depth synopsis of the major movements in the world's markets. The commentaries are arranged in easy-to-follow SWOT format with each section examining the strengths and weaknesses of the current market, and the opportunities and threats that could affect future performance. To view additional detailed information, please visit www.usfunds.com. The Investor Alert is updated each Friday at 8pm central standard time.