DALLAS (AP) -- Passenger flew fewer miles on Southwest Airlines Co. in August but they paid more per mile than a year ago.
The company, which also owns AirTran Airways, said Monday that passenger revenue for every seat flown one mile rose 4 percent compared with August 2012. That follows an increase of 4 percent to 5 percent for July.
The figure is a closely watched statistic in the airline business, and it rises when airlines are able to charge higher average fares either by raising prices or selling fewer tickets at discounted sale prices.
Last week, Delta and US Airways reported similar increases in the revenue figure. Helane Becker, an analyst for Cowen and Co., said the trend was due to strong demand and more late bookings — travelers who buy tickets on short notice usually pay higher fares.
Southwest said that traffic dropped 2 percent, as passengers flew 9.17 billion miles last month, down from 9.36 billion miles in August 2012.
Southwest and AirTran added seats, however, with capacity rising 1.4 percent. Part of that increase came from longer average trips — up 4.8 percent, to 1,007 miles.
Because traffic dropped and capacity increased, the average flight was less full. Occupancy averaged 81.3 percent last month, down from 84.2 percent in August 2012.
In the first eight months of the year, traffic has inched up by 0.8 percent, capacity has expanded by 1.6 percent, and the average flight has been 80.3 percent full, down from 80.9 percent in the same period last year.
Shares of Dallas-based Southwest rose 7 cents to $13.17 in midday trading Monday. They are down 9.5 percent from their high of $14.56 set on May 21. Over the past 52 weeks, they traded as low as $8.68 last October.