DENVER (AP) — Frontier Airlines canceled flights for the fifth straight day and arranged charter flights for some passengers Monday as hail damage kept many of its planes out of service at the height of the summer travel season.

With about 20 percent of its Airbus fleet in the shop, Frontier canceled 39 flights Monday and scratched another 15 flights Tuesday, bringing its total cancellations since Wednesday evening’s storm to nearly 220. However, the airline has contracted with charter airlines to replace 36 flights this week, and analysts didn’t expect the ordeal to significantly hurt Frontier’s earnings.

Hail Damage to Frontier Planes

The hail storm in Denver, Frontier’s main hub, damaged 18 of the airline’s 59 large Airbus planes. Five have returned to service, but Frontier issued a travel advisory Monday that said it was “still some distance from the finish line.”

Planes that suffer hail damage on the leading edge of their wings aren’t safe to fly with passengers because the dings prevent the aircraft from getting maximum lift, said Paul Czysz, professor emeritus of aeronautical engineering at St. Louis University. Frontier was able to fly the damaged planes, without passengers, to maintenance sites around the country.

 Hail Damage to Frontier Planes

The airline said it also was helping passengers find seats on other airlines and using aircraft from other subsidiaries of its parent company, Indianapolis-based Republic Airways Holdings Inc.

Frontier wasn’t the only airline affected. Denver’s largest carrier, United Airlines, has canceled at least 120 flights but, by Monday, only had to cancel seven smaller commuter flights—out of nearly 900 daily flights to and from Denver. Southwest Airlines Co. said three of its planes were damaged by hail, but, with 550 planes in its fleet, it didn’t have to delay or cancel any flights.

Mike Boyd, an aviation industry consultant, said Frontier was hurt by the timing of the storm because so many of its planes were at the airport at one time. He said the there would have been less damage if only the storm had hit two hours earlier or later. However, he thought Frontier was doing a good job of trying to accommodate passengers and wouldn’t suffer because of the hail damage.

“They’re spending top dollar to get these flights replaced as best they can,” he said.

Helane Becker, an analyst at Dahlman Rose & Co., said it’s harder for a small airline like Frontier to recover from weather problems since it doesn’t have as many planes as larger carrier, especially when so many airline seats are booked during the summer season. However, she said insurance would cover the lost use of the planes and she would only expect it to have a minor impact on the company’s earnings.