Frontier Group Holdingsthe parent company of budget airline Frontier, replaced its nearly decade-long CEO, Barry Biffle, with the carrier’s president, the company said Monday.

James Dempsey is taking over as interim CEO effective immediately.

“Jimmy has been an invaluable member of Frontier’s senior leadership team for more than 10 years and has played an instrumental role in the company’s evolution and growth during that time,” Board Chair Bill Franke said in a news release. “We believe Jimmy is uniquely qualified to guide our airline into the future.”

Biffle and Frontier declined to comment. Frontier said Biffle would stay on in an “advisory capacity” until the end of the year.

Biffle had been Frontier’s chief executive since March 2016 and has a more than three-decade career in airlines, including at the country’s longtime top budget carrier, Spirit, which is currently in its second bankruptcy in less than a year.

Frontier lost $190 million in the first nine months of the year, compared with net income of $31 million a year earlier.

Frontier had been in talks to merge with Spirit several times since early 2022, but none have solidified thus far.

Smaller budget airlines like Frontier have struggled to produce steady profits in the wake of the pandemic, as higher labor and other costs, consumer tastes shifting to international travel and higher-end seats, and an oversupply of domestic capacity have hurt financial results.

Biffle led some of Frontier’s initiatives in recent months to cater to customers seeking more space on board.

Frontier’s shares are down nearly 19% so far this year, while the NYSE Arca Airline Indexwhich tracks mostly U.S. airlines, is up more than 6%.