Southwest Airlines carries more passengers in March than a year ago, traffic falls on United

Southwest Airlines carried more passengers for more miles in March than a year ago, while United Airlines reported lighter traffic but offered a more upbeat forecast of first-quarter revenue.

Southwest said Thursday that it carried 10.4 million passengers last month, up 5.7 percent from March 2014, and they flew 10.24 billion miles, a 6.7 percent increase. Traffic rose 7.1 percent in the first quarter.

Southwest, the nation's fourth-biggest airline, added flights compared with a year ago, especially at its Dallas base. Still, the average plane was 84.5 percent full last month, up from 82.7 percent in March 2014.

Passenger revenue for every seat flown one mile, a closely watched figure in the airline business, rose about 1 percent in March, Southwest said. That number rises when an airline fills more seats or charges higher average fares.

In late-morning trading, shares of Dallas-based Southwest Airlines Co. were down 60 cents to $42.25.

United Continental Holdings Inc., the second-biggest airline operator behind American, said in a regulatory filing that the revenue per seat figure was between flat and up 5 percent for the first quarter, which was more upbeat than a January forecast of down 1 percent to up 1 percent. The modest improvement in outlook cheered investors.

March traffic on United fell 0.7 percent as passengers flew more on international routes but less on domestic ones. Regional flights on United Express carried 9.9 percent fewer passengers. For the whole first quarter, United's traffic rose 0.1 percent due to less travel on United Express.

The company's average March flight was 82.7 percent full, compared with 82.8 percent a year earlier.

Shares of Chicago-based United were up 63 cents to $61.18 late Thursday morning.