Cheap flights from California to Illinois from $101

The cheapest month to fly to Illinois from California is in September. Flight prices, which tend to average around $299, are often lower during this time because this is during the off-season. If you aren’t able to travel to Illinois during the month of September, then flying in August is also cheap. Prices for this month can be found on momondo for an average of $313.

The cheapest day to depart from California to Illinois is on a Thursday when prices can be found for as low as $400. Flights from California to Illinois on a Sunday will generally be more expensive and average around $480. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our most recent data shows that the best time of day to fly to Illinois is in the afternoon. Flights from California to Illinois during this time can be as low as $317. Flights at noon are often more expensive with an average ticket price of $492.

Fly from Los Angeles Los Angeles to Chicago O'Hare Intl for the best California - Illinois flight prices

You are more likely to see cheaper flights to Illinois from California when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $334 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from California for as low as $280 on momondo.

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

Southwest, Alaska Airlines, and Delta are the most popular carriers operating from California to Illinois

American Airlines, United Airlines and Frontier are the top three most popular airlines that fly to Illinois from California according to our data. American Airlines is the first choice among our users, with 43% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 8 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

As of June 2026, there are 303 flights per day flying from California to Illinois. The most common time of day flights depart is 10:00AM, with 48% of flights taking off at noon.

As of June 2026, 2,127 flights take off from California and land in Illinois each week. The most common flight departure day for this route is Mon, with 19% of weekly flights taking off on this day.