Over the years, Delta has managed to grow its revenue, while improving efficiency. For example, passenger revenue per available seat mile, or unit revenue, increased at an impressive 5.7% year over year in the second quarter. What's more, its five-year CAGR is approximately 6.5% -- another improvement.
Passenger load factor -- which measures how efficiently an airline fills seats and generates fare revenue -- increased to 86.3% from 84.8% in the first quarter of 2013. That compares well with the roughly 79% industry average calculated by the International Air Transport Association reported earlier this month.
Delta reported an operating margin of 14.9% during the most recent quarter compared to 9.4% over the same time last year. This is not just a one-off event, as the company has improved its operating margins in each of the last three years, growing from just 5.6% in 2011 to 9.0% in 2013. In its upcoming quarter, Delta expects to increase operating margin to 15%-17%.
These results are likely achievable considering Delta should see increasing demand in the coming months, as the June and September quarters typically see higher demand as vacation air-travel during these months increase.