A Frontier Airlines Airbus A321 airplane goes down the runway at Los Angeles International Airport on Jan. 2, 2025, in Los Angeles, California.

Frontier Airlines reported a 71% increase in airfare in the third quarter as the country's largest budget airline tried to pass along an even bigger jump in jet fuel prices.

Frontier's fare revenue averaged $67.82 per passenger in the third quarter, compared with $39.74 last year. Including the budget airline's many fees, such as for checked and carry-on luggage, total revenue per passenger rose 30% on the year to $138.22.

Customers kept booking despite the higher prices. Frontier's passenger count rose 18% to more than 9.8 million people in the quarter. That's a difference of 1.5 million passengers from last year.

The company said demand remains strong, even at these higher prices, but Frontier still lost money. The airline widened its third-quarter loss to $104 million from a $77 million loss a year earlier. Its fuel bill soared 82% to $425 million.

Frontier forecast potential adjusted profit in the fourth quarter, saying it expects to post an adjusted loss of 15 cents per share to adjusted earnings of as much as 5 cents per share.

Carriers from Delta Air Lines to Frontier have said customers are mostly continuing to book flights despite higher fares, but that record jet fuel prices, their biggest cost after labor, are eroding profits.

Frontier shares were up about 6% in early trading Wednesday.

Frontier had eclipsed Spirit Airlines as the biggest discount carrier in the country even before that airline collapsed in May.