Spirit Airlines is planning to furlough about 1,800 flight attendants, roughly a third of its cabin crew members, to cut costs as the budget airline struggles in its second bankruptcy in less than a year.

“As we work to return Spirit to profitability, we face difficult decisions about our network, our fleet, and ultimately our workforce,” John Bendoraitis, Spirit’s chief operating officer, wrote in a memo sent to flight attendants on Monday, which was reviewed by CNBC.

CNBC reported last week that the airline’s CEO Dave Davis had warned staff about job cuts as it looked to shrink its fleet in an effort to stabilize its business.

Some 800 Spirit flight attendants are already been out on voluntary leaves of absence, which has helped the airline avoid involuntary furloughs, Bendoraitis said.

“However, there is a limit to how many people can volunteer for these types of leave, and we have reached that mark,” he said.

The airline will first offer voluntary furloughs, so the final number of cabin crew members who will be affected wasn’t immediately clear.

Spirit didn’t immediately comment on the furloughs.

Spirit has also furloughed hundreds of pilots, and executives told the airline’s pilots’ union that it is seeking $100 million in cost cuts from its aviators.

Bendoraitis told the union, the Air Line Pilots Association, last week that that management is “available to continue to negotiate every day thereafter to reach a consensual agreement” by Oct. 1. Under the bankruptcy process, however, the airline could find relief outside of the pilots’ labor contract.