December was a record-breaking month for AirTran Airways, as the company saw increased traffic, capacity and number of enplaned passengers.
AirTran said paying passengers flew 1.53 billion miles last month, up from 1.46 billion miles in December 2008.
Capacity rose by 8.2 percent, to 1.98 billion available seat miles, which is a measure of one seat flown one mile.
Airlines expand capacity by adding flights or using larger planes with more seats. AirTran's capacity expansion came at a time when most larger airlines were cutting capacity.
With all the additional seats, AirTran's average occupancy or load factor fell to 77.7 percent from 79.8 percent a year earlier.
U.S. airlines battled a slowdown in travel demand during most of 2009, but discounters often fared better, as their lower fares attracted budget-conscious travelers during an economic slowdown.
For the full year, AirTran's traffic fell 1.9 percent, to 18.59 billion miles flown by paying passengers. Despite the December increase, AirTran cut capacity for the year by 2.2 percent, which allowed average occupancy to rise to 79.8 percent from 79.6 percent in 2008.
