Since 2000, most large passenger airlines suffered a sharp increase in their BLF. Some carriers chould not cover operating expenses even if they sold 100% of their seats at average airfares. This study focuses on three groups of major passenger airlines: The “recentrly bankrupt” - United, US Airways The “at risk” - airlines that have not filed for bankruptcy, but they have not achieved yearly profits over last two years. Consists of AA, Alaska, Continental, Delta, America West, and...