Mesa Air ( MESA) announced Wednesday that traffic, as measured in revenue passenger miles, rose 92.7% in February year-over-year. With February capacity as measured in available seat miles up 70.2% year-over-year, Mesa filled 66.8% of the seats on its flights, up from 59% a year ago. The explosive growth at Mesa, a regional carrier that flies for UAL ( UALAQ) unit United Airlines and US Airways ( UAIR), comes as the high-cost, hub-and-spoke carriers move to slash expenses and outsource less-profitable point-to-point routes to regional carriers who have lower costs and fly smaller planes. "Mesa's industry-leading growth is a direct result of our ability to offer a low-cost, quality product to our airline partners," said Mesa CEO Jon Ornstein in a statement. Shares of Mesa were up 27 cents, or 3%, to $9.27 in recent trading Wednesday. It's one of few airlines to post a gain. Another regional player, Alaska Air ( ALK), parent of Alaska Airlines and Horizon Air, also announced February results Wednesday morning. The carrier said Alaska's traffic increased 14.7% year-over-year, with capacity up 14.2%. That raised load factors, or the percentage of seats filled on every flight, to 67.7% from 67.4%. At Horizon, which flies smaller aircraft, traffic rose 28.8% in February, with capacity up 17.4%. Alaska Air shares stumbled, dropping 17 cents, or 0.7%, to $25.45.