United Airlines is extending their direct summer Chicago flights until Sept. 2, 2019.

The extension adds nearly a month to the flight schedule, creating a 20 percent increase in 2019 capacity between Great Falls and Chicago, according to a release from Great Falls International Airport, the Great Falls Area Chamber of Commerce and Great Fall Montana Tourism.

Tickets are available now for booking.

Direct Chicago flights are in their fourth year of operation, according to the release.

In 2018, United expanded Chicago flights to daily during the summer, resulting in 186 percent growth in passengers boarding flights from Great Falls and Chicago.

United experienced record boardings at Great Falls for both the summer and year, finishing 2018 with more than 17 percent growth in total boardings, according to the release.

The continued expansion of United’s Chicago service is a direct result of flight guarantees from the Low Cost Airline Initiative, which was funded by donations from local businesses and individuals including the Tourism Business Improvement District.

The Great Falls Airport has maintained the lowest average ticket price in Montana for the last five years of reported data, according to Federal Aviation Administration statistics.