US Airways Group Inc. (LCC) and AMR Corp.'s (AMR) American Airlines both reported a fall in traffic in September from a year earlier as they continued to cut capacity, although American Airlines' steeper capacity drop helped it post an improvement in the amount of seats filled.

In early trading US Airways shares rose 3.94% to $4.48, though they're down about 40% this year. AMR was up 3.75% at $7.74, having fallen about 25% in 2009.

AMR said the amount of seats filled on American Airlines flights was up to 79.4% last month from 76.6% a year earlier. Capacity fell 6.9%, more than offsetting a 3.5% drop in traffic. US Airways said its load factor was 79.3% in September, down 0.8 percentage point, as capacity was cut 0.6% and traffic fell 1.6%.

Meanwhile, passenger revenue per available seat mile, a key industry performance measurement, slumped 15% last month as carriers have been cutting fares in an attempt to stoke demand.

For the third quarter, load factor edged up to 84% from 83.9%, with capacity down 3.5% and traffic off 3.4%.

-By Joan E. Solsman, Dow Jones Newswires; 212-416-2291; joan.solsman@dowjones.com