DALLAS (AP) — Southwest Airlines Co. says a key measure of revenue rose as much as 5 percent in July even though flights weren't quite as full as a year ago.

Dallas-based Southwest on Wednesday estimated that its passenger revenue for each seat carried one mile was up 4 percent to 5 percent for the month.

Traffic fell 0.7 percent. Southwest boosted its flying capacity by 0.6 percent by adding longer flights. Because it added capacity as traffic fell, occupancy on its planes fell 1.1 percentage points, to 83.5 percent.

The overall number of flights declined 4.7 percent. The number of people Southwest carried fell 3.2 percent for the month.

For the first seven months of the year, traffic has risen 1.2 percent. Flying capacity is up 1.6 percent.

Copyright 2013 The Associated Press.