Southwest Airlines’ expansion helped its passenger traffic rise 8.6 percent in January.
The Dallas-based airline said Monday its passenger load factor — how full planes fly — fell 1.2 percentage points, to 75.1 percent, as capacity rose 10.2 percent.
Southwest, which has been adding flights since October, also said its unit revenue probably declined 1 percent from January 2014.
Neighboring carrier American Airlines saw its passenger traffic decline 2.8 percent in January as planes weren’t as full and capacity was flat.
The Fort Worth-based airline’s load factor declined 2.1 percentage points, to 78.2 percent.
American also said it expects first-quarter unit revenue to be down 2 percent to 4 percent. Due to the recent rise in fuel prices, the airline forecast fuel costs to be 10 cents higher than expected in the first quarter, with it paying between $1.81 to $1.86 per gallon of fuel.