Delta Air Lines' third-quarter profits topped Wall Street's expectations, as strong travel demand and higher fares boosted revenues while the carrier's fuel bill surged during the busy summer travel season.

The second-largest U.S. airline said Thursday its net income rose 13 percent in the three months ended Sept. 30 from a year earlier to $1.31 billion. Revenue rose 8 percent to $11.95 billion.

The carrier reported per-share adjusted earnings of $1.80, beating estimates of $1.74 a share, according to analysts polled by Refinitiv.

The airline's fuel bill rose 35 percent from a year earlier on an adjusted basis that included a $12 million benefit from its refinery. Higher airfares and strong sales of seats at the front of the plane helped lift revenue, Delta said. Revenue per-seat mile, a key industry metric, rose 4.3 percent in the quarter from a year earlier.

Looking ahead to the fourth-quarter, Delta said it expects earnings of $1.10 to $1.30 per share, roughly in line with analyst expectations. The carrier will post a profit of around $5 billion for the year, roughly in line with 2017, despite a $2 billion increase in fuel costs, thanks in part to strong demand and higher fares, CEO Ed Bastian told CNBC. Hurricane Florence last month cost Delta $30 million during the quarter.

Demand for premium cabin seats, such as those in first and business class, rose 20 percent.

In recent years, Delta has been aiming to sell more premium-cabin seats instead of filling them by upgrading travelers. The airline now sells about half of those seats, Bastian told CNBC.

Delta shares were up more than 3 percent early trade on Thursday. Other airline shares also rose, a relief for the sector that has largely struggled this year as an increase in fuel prices dented profits. Delta shares are off more than 8 percent in 2018. American Airlines is down more than 37 percent — more than any other U.S. airline this year — while Southwest Airlines' shares are down more than 10 percent. United Airlines, however, has posted a more than 20 percent gain.

Delta executives will hold an investor call at 10 a.m. ET.