It's possible to leverage your credit card habits so that you can accrue those valuable airline miles, but still keep yourself out of financial trouble. It's an art form, and it helps if you're a frequent business traveler, but here's how to create a financial masterpiece of your own. First, the bad news. Going into an airline cards reward deal, the odds of coming out ahead are against you, especially if you're not paying attention. The Web site CardWeb.com recently tallied the pertinent numbers on 11 major U.S. airlines that sponsor credit cards. The site found that while the cards, on average, returned 1.4% in the form of free air miles, they take a bigger bite in the form of an interest rate that's higher than regular credit cards. CardWeb calculates that a $3,000 balance, kept for over two years on an airline card, would cost you $964 in interest and fees (but you would earn a $338 airline ticket, the company says). In that calculation, the math doesn't really add up, and that's not even including the annual fee that many airline card issuers charge consumers. But if you take to the friendly skies on a regular basis, you can gain the upper hand over the card carrier. The keys are using your card frequently, paying your bills on time, and flying the same airline over and over again. If that sounds like the make-up of a business traveler right out of central casting, then there you go. Business travelers can use the cards often, get reimbursed by their employers and then pay off the cards in a timely fashion. In this case, the airline cards can be a good deal.