Frontier Airlines will end its twice daily round-trip service from Tulsa to Denver International Airport on April 5, industry officials said Thursday.

Denver-based Frontier, whose Lynx Aviation subsidiary operates morning and afternoon flights to Denver from Tulsa International Airport, advised Airports Director Jeff Mulder about the change Thursday.

Frontier began three-a-day Tulsa- Denver flights several years ago but dropped them when the company filed bankruptcy in 2008. Frontier resumed its Tulsa-Denver service last year with two daily round trips.

Republic Airways Holdings Inc., Frontier's parent company, said Thursday it will shut down Lynx Aviation, the regional flying unit it acquired along with Frontier in 2009.

Lynx has 11 Bombardier Q400 propeller planes. Indianapolis-based Republic said it will begin phasing them out April 6, and they'll all be gone by mid-September. The changes will mean 175 people will lose their jobs initially, with more cuts expected.

Most flying done by Lynx will be replaced by regional jets operated by Republic crews.