Amid reduced competition in Atlanta, lower fuel prices and other factors, Delta Air Lines swung to a $685 million profit for the second quarter.

Delta President Ed Bastian said the airline’s Atlanta hub had “solid performance for the quarter,” including a 3 percent hike in profit margin over last year. Atlanta’s Hartsfield-Jackson International Airport is Delta’s largest hub.

Competitor Southwest Airlines, which acquired AirTran Airways and is gradually integrating it into Southwest, has cut flights in Atlanta.

Delta’s executive vice president of network planning, Glen Hauenstein, said Southwest and AirTran combined will be down to about 150 daily departures from Atlanta. “Certainly that’s an improved competitive environment for us here in Atlanta,” he said.

AirTran previously had about 220 daily flights from Atlanta.

Delta said it would have an $844 million profit — a record June quarter result for the company — excluding so-called “special items” such as a $125 million charge to adjust the value of future fuel hedges and a $34 million charge primarily for fleet restructuring.

Delta’s passenger revenue grew 0.7 percent, but it had a decrease in cargo and other revenue, resulting in a $25 million decline to about $9.7 billion in total operating revenue for the quarter.

Also, the Trainer refinery in Pennsylvania that Delta acquired last year has yet to break even or make a profit. Delta said the refinery generated a $51 million loss because of higher costs to meet renewable fuel standards. Otherwise, the refinery would have broken even, the airline said. However, Delta said it is still saving on fuel costs as a result of the refinery.