CHICAGO (AP) – United Airlines said Monday that January traffic rose, and it collected more revenue from each passenger.

United said it collected 9.5 percent to 11.5 percent more for each passenger flown one mile in January compared with January 2009.

Throughout last year airlines struggled to raise fares, so any increase in so-called unit revenue is going to be welcomed by the industry.

For instance, United said last year's unit revenue fell 6.7 percent in January 2009, 11.2 percent in February, and 15 percent in March compared with a year earlier. Monday was the first time United released monthly unit revenue numbers.

United said traffic across its system rose 2.4 percent, to 8.77 billion revenue passenger miles. A passenger mile is one passenger flown one mile. Capacity fell 2 percent to 11.17 billion available seat miles. That means planes were 3.4 percentage points fuller; occupancy rose to 78.5 percent in January.

The traffic increase was not spread evenly around United's system.

United's regional affiliates carried more than a quarter of its traffic.

Flying on those affiliates jumped 22.8 percent to 1.13 billion revenue passenger miles in January, compared with a year earlier.