Frontier Airlines is suspending its Sioux City to Denver passenger service. The airline notified Sioux Gateway Airport director Curt Miller that it’s starting what it calls a “seasonal shut down” of flights on October 24th. “That was a surprise to us,” Miller says. “We weren’t expecting to have any reduction in service. They indicated it was a seasonal adjustment. They said they would work with us in the future to talk about service again in 2015.”

The change in schedule appeared in the Frontier Airlines reservation system over the weekend. It eliminates any flights to Denver from Sioux City through the Christmas holidays and for much of the ski season. Miller says it’s frustrating to lose the service because Sioux City has been filling the flights with passenger numbers in July exceeding 90-percent of the available seats.

“I don’t know any more than what they gave me as far as an explanation,” he says. “All I can base it on is our enplanement numbers and they’ve been over 90% full, so the rest of the decision has to be based on other factors.” Frontier says it’s reallocating aircraft for its 4th quarter schedule, so several markets will be affected by the changes. Anyone with questions should contact the airline at 800-432-1359.

(Reporting by Woody Gottburg, KSCJ, Sioux City)