Mesa Air Group's (NASDAQ:MESA) traffic figures continue to take off. But the regional air carrier's future is unclear as it contemplates options for coping with its dependence on major carriers.

Mesa reported that May's passenger miles, or the number of revenue-paying passengers times the number of miles flown, surged 80% to 464.1 million, versus 257.3 million in May 2003. In addition, the firm's load factor, or percentage of available seating filled with passengers, rose to 73.4% from 65.1%.

Unfortunately, these numbers are clouded by Mesa's continued reliance on ailing US Airways (NASDAQ:UAIR) for a healthy chunk of revenue. With US Airways contemplating bankruptcy, investors are understandably cagey about Mesa's prospects. In an extreme scenario under which US Airways liquidates operations, Mesa might be left with a gaping hole in its revenue stream.

Nevertheless, Mesa is not without resources. The company had $217 million in cash on its balance sheet as of March 31 and is profitable. Some reports have raised the possibility that Mesa may even go its own way as a low-cost regional carrier. Doing so, though, would be a significant undertaking that would probably negatively affect profitability.

In this year's first quarter, Mesa's revenue per seat mile was 13.2 cents, while operating cost per seat mile was 12.8 cents. Cost per seat mile seems high, but so does revenue. Compare the numbers to the same metrics for low-cost leader Southwest Airlines (NYSE:LUV) -- 8.07 cents for revenue and 7.82 cents for cost -- and it appears Mesa is performing well.

At the moment, though, Mesa derives 99% of its passenger revenue from code-sharing agreements with other airlines, which, in addition to US Airways, include United Airlines, America West (NYSE:AWA), and Midwest Air (NYSE:MEH). Under these arrangements, Mesa shares partners' reservation systems and participates in joint advertising, allowing it to keep costs down. If the carrier goes independent, presumably it will have to shoulder more of these expenses, which could throw its operating performance out of whack.

In any case, Mesa seems to have the wherewithal to chart its own course. Whatever path it chooses, it should be an interesting ride.

Fool contributor Brian Gorman is a freelance writer living in Chicago, Ill. He does not own shares of any companies mentioned here.