Imagine a scenario where I start a business... say a lemonade stand. I borrow $100 from my dad to build the stand, and pay him back $1 a day in interest. Every day I sell 3 lemonades for $.50 each, and each one costs me $.25. At the end of the day I've made an "operating profit" of $.75. After I pay back my dad his $1, I've lost $.25 each day. This is my net loss. Keep this up in the long term, and my total debt just keeps increasing (reverse compound interest). This is the position Virgin America is in now. If they want to make it long term, they need to do a lot better.
More accurately stated.... Imagine a scenario where you have 100 dollars in your pocket and you use it to start a lemon aid stand. You set up the lenomaid stand as an LLC and pay yourself an exorbitant Interest rate on the 100 dollars the lenomaid stand borrowed. The lemonaid stand is profitable when you account for only the price of water, sugar and lemons, but when you figure in the cost of the interest you are paying to yourself, the lemonaid stand is no longer profitable. That's OK because the lemonaid stand now doesn't pay any corporate income tax. All the proceeds are taxed at the much lower capital gains tax rate. You can also tell the employees of your lemonaid stand that you are too poor to pay them industry standard wages because no one has enough attention span to understand your voodoo accounting practices. Years later during an economic boom cycle you IPO the lemonaid stand and sell it to wall street investors for $300.