American Airlines said its passenger traffic rose 4.8 percent as the company added 2.2 percent more capacity to its network in July.
The Fort Worth, Texas-based airline said its load factor grew to 87.3 percent, up 2.2 percentage points compared to July 2014.
The company reiterated to investors that it expects unit revenues to be down 6 to 8 percent in the third quarter.
Meanwhile, Southwest said passenger traffic was up 8.2 percent in July, as the airline continues to add more flights to its network in Dallas and Washington, D.C.
The Dallas-based carrier said its capacity grew 7.0 percent. Its load factor was a record 87.7 percent, up 1.0 percentage points from July 2014.
Southwest told investors it expects its unit revenues to decrease about 1 percent for the third quarter compared to the same quarter last year.