The number of enplaned passengers on AirTran Airways' flights increased 1.7 percent to 1.979 million in December from 1.946 for the same time a year ago.
Passengers for the year, however, fell 2.5 percent to 24.0 million, the airline reported.
Load factors, how full the aircraft are, totaled 77.7 percent in December, down from 79.8 percent a year ago.
For 2009, load factors averaged 79.8 percent, up from 79.6 percent for 2008.
AirTran operates daily flights from Wichita to Atlanta.