Cheap flights from Calgary to Illinois from C$ 218

In general, January is the cheapest month to fly from Calgary to Illinois. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around C$ 354. If you don’t want to visit Illinois in January, then you should wait until May to fly from Calgary, when ticket prices are also cheap, with an average price of C$ 364.

According to our data, Friday is the cheapest day to fly to Illinois from Calgary. The lowest ticket price found for a Friday departure recently was C$ 589. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. The most expensive day to fly to Illinois is Sunday, with ticket prices averaging around C$ 1,113.

Our most recent data shows that the best time of day to fly to Illinois is in the morning. Flights from Calgary to Illinois during this time can be as low as C$ 705. If you have a flexible travel schedule, then try to avoid flying at noon when prices are C$ 1,083 on average. Flights to Illinois from Calgary at noon are generally more expensive because this time of day is more convenient for travellers’ schedules.

Fly from Calgary to Chicago O'Hare Intl for the best Calgary - Illinois flight prices

You are more likely to see cheaper flights to Illinois from Calgary when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around C$ 429 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Calgary for as low as C$ 309 on momondo.

There are 4 cabin classes available to choose from on Calgary to Illinois flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

United Airlines, Delta, and Porter Airlines are the most popular carriers operating from Calgary to Illinois

WestJet, American Airlines and United Airlines are the top three most popular airlines that fly to Illinois from Calgary according to our data. WestJet is the first choice among our users, with 47% of people opting to fly with this airline when travelling to Illinois. Keep in mind that there are 6 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

10 flights are operational daily from Calgary to Illinois as of September 2026. The most popular departure time for this route is 12:00p.m., with 62% of flights per day taking off in the afternoon.

The number of flights available between Calgary and Illinois is 75 per week as of September 2026. The most frequent departure day is Fri, with 21% of weekly flights leaving on this day.