Southwest Airlines (NYSE: LUV ) saw small increases in several of its key metrics last month, and for the initial quarter of 2013. For the month, the company's revenue passenger miles grew by 4% over March 2012's number, to hit 9.4 billion. Available seat miles increased by 3.8% on a year-over-year basis, to 11.5 billion. Load factor -- i.e., airplane occupancy -- grew by 0.2 percentage points over the same time frame, coming in at 82%.
In terms of passenger figures, the total number of revenue passengers carried saw a 3.1% year-over-year rise last month, coming in at 9.9 million. Overall, slightly more than 12 million riders were enplaned, a 2.6% gain from March 2012.
On a quarterly basis, RPMs amounted to 23.8 billion, a 0.3% increase over March 2012's number. ASMs also saw an uptick, by 0.6%, to 30.8 billion. Load factor for the three months was slightly down on a comparative basis, however -- it was 77.1%, against 77.3% in the same quarter last year.