A few more empty seats are showing up on American Airlines, US Airways flights

Passenger traffic on American Airlines and US Airways was nearly flat last month, and the carrier expects that a key revenue figure will grow no more than 2 percent for the third quarter.

American Airlines Group Inc. said Tuesday that passengers flew 20.02 billion miles last month, only 8 million miles more than August 2013. Travel dipped slightly on both domestic and international routes. That roughly matched the performance of United Airlines but lagged gains at Delta and Southwest.

American and US Airways increased passenger-carrying capacity last month by 1.1 percent — that is usually done by adding flights or using bigger planes. The biggest increases were on routes over the Pacific and Atlantic.

With traffic on American and US Airways failing to keep up with capacity, there were a few more empty seats. The average flight was 84.6 percent full, down from 85.5 percent in August 2013.

The parent company said that based on July and August results and a forecast for September, it expects a key revenue figure to be flat to up about 2 percent for the third quarter. The figure — revenue for every seat flown one mile — is watched closely in the airline business.

Shares of American Airlines rose 8 cents to $38.31 in morning trading. They began the day up 51 percent in 2014.