Delta traffic down; AirTran traffic up

Delta Air Lines had a 5 percent decline in passenger traffic in January, as it cut flight capacity by 5.6 percent year-over-year. Atlanta-based Delta’s planes averaged 76.6 percent full in the month, up half a point from a year earlier.

AirTran had a 6.8 percent increase in passenger traffic on an 8.6 percent increase in capacity in January. Its planes averaged 72 percent full, down 1.2 points from a year earlier. Orlando-based AirTran has its largest hub in Atlanta.

At both carriers, passenger traffic is measured in revenue passenger miles, while capacity is measured in available seat miles.