Shares in American airline Delta (NYSE:DAL) fell on Thursday, after announcing a 20 percent fall in profits for the 2017 financial year.

The group made a profit of $1.22 billion over the past 12 months, a fall of just over 20 percent from last year’s figure of $1.55 billion.

This came despite a 2.5 percent increase in passenger unit revenue, and a 0.4 percent larger capacity in the second quarter of 2017. The airline had to contend with a rise in operating expenses during the final quarter, as higher salaries and fuel costs dug into profits.

“The June quarter represented the peak for non-fuel cost pressures this year and we expect our CASM (cost per available seat mile) trajectory to moderate to approximately 2 percent for the September quarter,” Delta Chief Financial Officer Paul Jacobson said in a statement.

Delta Air Lines is the second largest US airline by passenger traffic, and have consistently stayed clear of competing as a budget airline. Instead, it has marketed itself “a carrier of choice”, with better service, seating, in-flight entertainment and loyalty programmes.

Shares in Delta sunk on Thursday, and are currently trading down 1.10 percent at 54.86 (1515GMT).