The airline is in the middle of a plan to reduce costs by culling unprofitable routes and drumming up revenue with higher-priced seats.

Unit costs in 2025 will rise as much as 7% excluding fuel, the airline said Tuesday in a statement, outpacing analysts’ estimates on higher spending for compensation and aircraft maintenance. JetBlue shares fell as much as 18% as markets opened in New York, their biggest slump since Aug. 12.

JetBlue Airways forecast higher costs and unit revenue below analysts' expectations for the first quarter on Tuesday, sending the New York-based carrier's shares down 14% in morning trade.

JetBlue’s fourth-quarter results beat expectations, but the outlook for a key revenue metric was below forecasts.