Despite the fact that its total trips flown fell by nearly 4% in June, today Southwest Airlines (NYSE:LUV) announced its revenue passenger miles increased by 2.2% from a year ago to 10.1 billion.

In addition to the impressive increase in passenger miles (one paying passenger flown one mile), Southwest also noted its passenger revenue per available seat mile (PRASM) is estimated to have grown between 7% and 8% percent during the month of June, compared to June 2013. In total for the second quarter of 2014, Southwest expects the growth in its PRASM to be greater than 8%, relative to the second quarter of last year.

Southwest also saw impressive growth in its June load factor -- the percentage of a plane filled with paying passengers -- which rose from 85% last year to 86.1%. This marked another month of improvement in this measure of efficiency, and through the first six months of the year Southwest saw its load factor rise 2.2 percentage points to 81.7%.

During the first quarter of the year Southwest posted a record quarterly profit of $152 million. June marked another month of impressive growth for Southwest in its ability to drive profitability, and knowing the same was true for April and May as well, the second quarter seems to be poised as another strong one for the airline.