Several U.S. airlines are reporting a sharp decline in consumer travel demand at a time when lower fares, pricier jet fuel, and more seats entering the market are complicating the financial outlook.

Ultra-low-cost airlines Spirit and Frontier are predicting losses for the third quarter. Frontier said Wednesday that its expected third-quarter profit has instead turned to red ink as “sales have been trending below historical seasonality patterns” in recent weeks.

“You’ve gone from industry sales being up, to flat, to now being down versus 2019, and that’s coming at a time that capacity is going up,” Frontier CEO Barry Biffle said Wednesday at a Morgan Stanley investor conference. “And then the third leg of that stool is fuel. So you’ve got fuel, capacity and demand all going the wrong direction.”