Low-cost carrier Frontier Airlines is ending its year-round service between Rockford and Denver.
The Denver-based airline says the route has brought in good business in the summers, but not the rest of the year.
The change to summer-only service goes into effect Sept. 7.
The (Rockford) Register Star reports that flights to Denver represent about 7 percent of passenger traffic at the Chicago Rockford International Airport.
Frontier began offering three weekly roundtrips between the cities in December 2011.
Spokeswoman Kate O'Malley tells the newspaper that "market performance outside of summer peak did not justify maintaining year-round service."
Under an agreement that has now expired, the airport was paying the airline about $30,000 a month for the first nine months of the deal to help support year-round service.