Cheap flights from Illinois to the United States from $86

In general, January is the cheapest month to fly from Illinois to United States. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $269. If you aren’t able to travel during the month of January, then book flights to United States from Illinois during October instead. Flights to United States in October, while not as cheap as those in January, still average around $283.

According to our data, Friday is the cheapest day to fly to United States from Illinois. The lowest ticket price found for a Friday departure recently was $272. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. If your travel schedule is flexible, try to avoid departing on a Monday because tickets tend to average around $401. These prices are subject to change though, so be sure to set up a Price Alert for flights to United States.

The cheapest time of day to fly to United States is in the evening when flights can be purchased for as low as $281. Try not to purchase tickets in the afternoon because they tend to be around $385. Of course, these prices can vary depending on the time of year and what airport you fly to.

Fly from Belleville to Las Vegas Harry Reid Intl for the best Illinois - United States flight prices

You are more likely to see cheaper flights to United States from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to United States for around $212 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to United States from Illinois for as low as $168 on momondo.

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

Frontier, United Airlines, and Delta are the most popular carriers operating from Illinois to United States

United Airlines, American Airlines and Frontier are the top three most popular airlines that fly to United States from Illinois according to our data. United Airlines is the first choice among our users, with 39% of people opting to fly with this airline when traveling to United States. Keep in mind that there are 10 different airlines that fly to United States on a routine basis, so you have a few additional options to choose from.

459 flights are operational daily from Illinois to United States as of August 2026. The most popular departure time for this route is 5:00PM, with 38% of flights per day taking off at noon.

As of August 2026, there are 3,216 flights per week flying from Illinois to United States. The most common day of the week flights depart is Fri, with 19% of flights taking off on this day.