U.S. Airways (NYSE:LCC) reported record load factor in January as an increase in demand outpaced growth in capacity, and passenger revenue per available seat mile climbed 10%.

The Tempe, Ariz.-based carrier said mainline revenue passenger miles for the month were up 3.8% to 4.6 billion, while capacity grew 3.1% to 5.9 billion available seat miles, bringing load factor up half a percentage point to 78.8%.

Despite “runway construction at our hub in Phoenix for most of the month, our team delivered its best January operational performance in the history of our company,” U.S. Airways CEO Scott Kirby said in a statement.

Demand was particularly strong for domestic flights, with mainline revenue passenger miles growing 6.1% to 3.6 billion, offsetting flat revenues in its Atlantic region and a 7% drop to 442 million in Latin America.

In the first four weeks of 2012, the carrier’s preliminary on-time performance was 85% with a completion factor of 99.2%, according to the U.S. Dept. of Transportation.

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