How many flights depart from Colorado to Illinois on average per day?

As of August 2026, 70 flights take off from Colorado and land in Illinois each day. The most common flight departure time for this route is 12:00PM, with 54% of daily flights taking off in the afternoon.

What is the cheapest airline that flies from Colorado to Illinois?

Southwest, United Airlines, and Delta are the most popular carriers operating from Colorado to Illinois

How many flights depart from Colorado to Illinois on average per week?

The number of flights available between Colorado and Illinois is 495 per week as of August 2026. The most frequent departure day is Sun, with 23% of weekly flights leaving on this day.

What airlines fly to Illinois?

United Airlines, American Airlines and Frontier are the top three most popular airlines that fly to Illinois from Colorado according to our data. United Airlines is the first choice among our users, with 44% of people opting to fly with this airline when traveling 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.

How long is the flight from Colorado to Illinois?

The flight from Colorado to Illinois depends on which airports you’re departing and arriving from and whether or not you have a layover. If you fly from Denver (a popular airport in Colorado) to Chicago O'Hare Intl Airport (the most popular airport in Illinois), then the flight time is 2h 23m on average. If you fly from Colorado Springs (another popular airport in Colorado) to Chicago O'Hare Intl Airport, then the average flight time is 2h 43m.

When did momondo last update prices for flights from Colorado to Illinois?

Prices for flights from Colorado to Illinois are updated daily.

How many operators does momondo search for flights from Colorado to Illinois?

As of August 2026, there are 6 operators available to choose from for flights from Colorado to Illinois.

How old do you have to be to fly from Colorado to Illinois?

The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Colorado to Illinois.

What documentation or ID do you need to fly to Illinois?

The required travel and health documents for your Illinois trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Illinois. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

$43 Cheap Flights from Colorado to Illinois in 2026

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Colorado to Illinois

Round-trip

One-way

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Cheap round-trip flights

Enter your travel dates to find the best prices.

10:20 am - 1:19 pmDEN Denver Intl-PIA Greater Peoria

1h 59mnonstop

5:24 pm - 6:44 pmPIA Greater Peoria-DEN Denver Intl

2h 20mnonstop

$114Allegiant Air

Thu, Oct 29 - Sun, Nov 1

10:20 am - 1:19 pmDEN Denver Intl-PIA Greater Peoria

1h 59mnonstop

5:24 pm - 6:44 pmPIA Greater Peoria-DEN Denver Intl

2h 20mnonstop

$138Allegiant Air

Sun, Nov 1 - Sun, Nov 1

4:12 pm - 7:15 pmDEN Denver Intl-STL Lambert-St Louis

2h 03mnonstop

8:34 pm - 11:04 pmSTL Lambert-St Louis-DEN Denver Intl

27h 30m1 stop Orlando

$169Frontier

Thu, Oct 15 - Thu, Oct 22

6:38 pm - 11:32 amDEN Denver Intl-STL Lambert-St Louis

15h 54m1 stop Las Vegas Harry Reid Intl

8:10 pm - 9:39 pmSTL Lambert-St Louis-DEN Denver Intl

2h 29mnonstop

$170Frontier

Fri, Oct 2 - Mon, Oct 5

7:00 am - 10:20 amDEN Denver Intl-MDW Chicago Midway

2h 20mnonstop

5:05 pm - 6:45 pmMDW Chicago Midway-DEN Denver Intl

2h 40mnonstop

$172Southwest

Wed, Oct 21 - Sat, Oct 24

8:25 pm - 11:50 pmDEN Denver Intl-MDW Chicago Midway

2h 25mnonstop

7:00 am - 8:30 amMDW Chicago Midway-DEN Denver Intl

2h 30mnonstop

$177Southwest

Fri, Sep 11 - Mon, Sep 14

9:10 pm - 11:48 amDEN Denver Intl-ORD Chicago O'Hare Intl

13h 38m1 stop Minneapolis St Paul

6:30 am - 8:15 amORD Chicago O'Hare Intl-DEN Denver Intl

2h 45mnonstop

$185Multiple Airlines

Fri, Sep 18 - Tue, Sep 22

8:55 pm - 12:23 amDEN Denver Intl-ORD Chicago O'Hare Intl

2h 28mnonstop

6:39 pm - 11:46 pmORD Chicago O'Hare Intl-DEN Denver Intl

6h 07m1 stop Minneapolis St Paul

$185Multiple Airlines

Mon, Oct 5 - Fri, Oct 9

5:35 pm - 8:46 pmDEN Denver Intl-STL Lambert-St Louis

2h 11mnonstop

4:45 pm - 6:15 pmSTL Lambert-St Louis-DEN Denver Intl

2h 30mnonstop

$200United Airlines

Sat, Sep 5 - Sat, Sep 12

1:27 pm - 4:34 pmDEN Denver Intl-STL Lambert-St Louis

2h 07mnonstop

4:40 pm - 6:10 pmSTL Lambert-St Louis-DEN Denver Intl

2h 30mnonstop

$200United Airlines

Wed, Sep 2 - Sun, Sep 6

Cheap last minute flights

Enter your travel dates to find the best prices.

5:05 pm - 8:52 pmDEN Denver Intl-ORD Chicago O'Hare Intl

2h 47mnonstop

2:41 pm - 4:45 pmORD Chicago O'Hare Intl-DEN Denver Intl

3h 04mnonstop

$224Frontier

Wed, Aug 12 - Sat, Aug 29

5:05 pm - 8:52 pmDEN Denver Intl-ORD Chicago O'Hare Intl

2h 47mnonstop

5:59 pm - 7:33 amORD Chicago O'Hare Intl-DEN Denver Intl

14h 34m1 stop Orlando

$231Frontier

Wed, Aug 12 - Sat, Aug 29

5:44 pm - 9:45 pmDEN Denver Intl-ORD Chicago O'Hare Intl

3h 01mnonstop

10:15 pm - 11:59 pmORD Chicago O'Hare Intl-DEN Denver Intl

2h 44mnonstop

$311American Airlines

Fri, Aug 14 - Sun, Aug 16

2:21 pm - 6:15 pmDEN Denver Intl-ORD Chicago O'Hare Intl

2h 54mnonstop

6:45 am - 8:25 amORD Chicago O'Hare Intl-DEN Denver Intl

2h 40mnonstop

$311American Airlines

Thu, Aug 13 - Sun, Aug 16

4:27 pm - 7:37 pmDEN Denver Intl-PIA Greater Peoria

2h 10mnonstop

5:23 pm - 6:48 pmPIA Greater Peoria-DEN Denver Intl

2h 25mnonstop

$321Allegiant Air

Thu, Aug 13 - Sun, Aug 16

4:27 pm - 7:37 pmDEN Denver Intl-PIA Greater Peoria

2h 10mnonstop

5:23 pm - 6:48 pmPIA Greater Peoria-DEN Denver Intl

2h 25mnonstop

$331Allegiant Air

Thu, Aug 13 - Sun, Aug 16

4:42 pm - 8:45 amDEN Denver Intl-PIA Greater Peoria

39h 03m2 stops Sioux Falls Joe Foss Field Tampa St. Petersburg

10:07 am - 11:26 amPIA Greater Peoria-DEN Denver Intl

2h 19mnonstop

$349Multiple Airlines

Fri, Aug 14 - Thu, Aug 20

8:31 pm - 4:00 pmDEN Denver Intl-PIA Greater Peoria

18h 29m1 stop Phoenix Sky Harbor Intl

10:07 am - 11:26 amPIA Greater Peoria-DEN Denver Intl

2h 19mnonstop

$367Multiple Airlines

Fri, Aug 14 - Thu, Aug 20

5:30 pm - 8:50 pmDEN Denver Intl-PIA Greater Peoria

2h 20mnonstop

8:45 am - 10:26 amPIA Greater Peoria-DEN Denver Intl

2h 41mnonstop

$389United Airlines

Fri, Aug 14 - Mon, Aug 17

5:30 pm - 8:50 pmDEN Denver Intl-PIA Greater Peoria

2h 20mnonstop

8:45 am - 10:26 amPIA Greater Peoria-DEN Denver Intl

2h 41mnonstop

$389United Airlines

Fri, Aug 14 - Sun, Aug 16

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Frontier flights from Colorado to Illinois

Our best Frontier deals on Colorado to Illinois flight tickets

Frontier

Oct 15

DEN4:12 pmDenver Intl

2h 03m

STL7:15 pmLambert-St Louis

Oct 22

STL8:34 pmLambert-St Louis

27h 30m

1 stop

DEN11:04 pmDenver Intl

$169

Frontier

Sep 10

DEN6:30 amDenver Intl

12h 05m

1 stop

ORD7:35 pmChicago O'Hare Intl

Sep 13

ORD6:30 amChicago O'Hare Intl

2h 45m

DEN8:15 amDenver Intl

$170

Frontier

Sep 25

DEN8:55 pmDenver Intl

2h 28m

ORD12:23 amChicago O'Hare Intl

Sep 28

ORD6:30 amChicago O'Hare Intl

2h 45m

DEN8:15 amDenver Intl

$171

American Airlines flights from Colorado to Illinois

Our best American Airlines deals on Colorado to Illinois flight tickets

American Airlines

Sep 3

DEN7:20 amDenver Intl

6h 25m

1 stop

STL2:45 pmLambert-St Louis

Sep 6

STL10:16 amLambert-St Louis

6h 13m

1 stop

DEN3:29 pmDenver Intl

$220

American Airlines

Sep 14

COS5:01 amColorado Springs

2h 49m

ORD8:50 amChicago O'Hare Intl

Sep 23

ORD10:55 amChicago O'Hare Intl

2h 53m

COS12:48 pmColorado Springs

$261

American Airlines

Sep 14

COS5:01 amColorado Springs

2h 49m

ORD8:50 amChicago O'Hare Intl

Sep 23

ORD1:46 pmChicago O'Hare Intl

5h 50m

1 stop

COS6:36 pmColorado Springs

$271

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Quickest round-trip

DenverPeoria

DEN Denver Intl - PIA Greater Peoria

DENPIA

Denver Intl

Thu 10/29

10:20 am-1:19 pm

Nonstop1h 59m

Greater Peoria

Sun 11/1

5:24 pm-6:44 pm

Nonstop2h 20m

$114

DenverPeoria

DEN Denver Intl - PIA Greater Peoria

DENPIA

Denver Intl

Sun 11/1

10:20 am-1:19 pm

Nonstop1h 59m

Greater Peoria

Sun 11/1

5:24 pm-6:44 pm

Nonstop2h 20m

$138

DenverSt. Louis

DEN Denver Intl - STL Lambert-St Louis

DENSTL

Denver Intl

Thu 10/15

4:12 pm-7:15 pm

Nonstop2h 03m

Lambert-St Louis

Thu 10/22

8:34 pm-11:04 pm

1 stop27h 30m

$169

DenverSt. Louis

DEN Denver Intl - STL Lambert-St Louis

DENSTL

Denver Intl

Fri 10/2

6:38 pm-11:32 am

1 stop15h 54m

Lambert-St Louis

Mon 10/5

8:10 pm-9:39 pm

Nonstop2h 29m

$170

DenverChicago

DEN Denver Intl - MDW Chicago Midway

DENMDW

Denver Intl

Wed 10/21

7:00 am-10:20 am

Nonstop2h 20m

Chicago Midway

Sat 10/24

5:05 pm-6:45 pm

Nonstop2h 40m

$172

DenverChicago

DEN Denver Intl - MDW Chicago Midway

DENMDW

Denver Intl

Fri 9/11

8:25 pm-11:50 pm

Nonstop2h 25m

Chicago Midway

Mon 9/14

7:00 am-8:30 am

Nonstop2h 30m

$177

DenverChicago

DEN Denver Intl - ORD Chicago O'Hare Intl

DENORD

Denver Intl

Fri 9/18

9:10 pm-11:48 am

1 stop13h 38m

Chicago O'Hare Intl

Tue 9/22

6:30 am-8:15 am

Nonstop2h 45m

$185

DenverChicago

DEN Denver Intl - ORD Chicago O'Hare Intl

DENORD

Denver Intl

Mon 10/5

8:55 pm-12:23 am

Nonstop2h 28m

Chicago O'Hare Intl

Fri 10/9

6:39 pm-11:46 pm

1 stop6h 07m

$185

DenverSt. Louis

DEN Denver Intl - STL Lambert-St Louis

DENSTL

Denver Intl

Sat 9/5

5:35 pm-8:46 pm

Nonstop2h 11m

Lambert-St Louis

Sat 9/12

4:45 pm-6:15 pm

Nonstop2h 30m

$200

DenverSt. Louis

DEN Denver Intl - STL Lambert-St Louis

DENSTL

Denver Intl

Wed 9/2

1:27 pm-4:34 pm

Nonstop2h 07m

Lambert-St Louis

Sun 9/6

4:40 pm-6:10 pm

Nonstop2h 30m

$200

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

How to get the cheapest flight ticket from Colorado to Illinois

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Other information

What is the cheapest month to fly to Illinois?

The cheapest month to fly to Illinois from Colorado is in January. Flight prices, which tend to average around $247, 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 January, then flying in September is also cheap. Prices for this month can be found on momondo for an average of $261.

What is the cheapest day to depart on your flight to Illinois?

The cheapest day to depart from Colorado to Illinois is on a Friday when prices can be found for as low as $323. Flights from Colorado to Illinois on a Sunday will generally be more expensive and average around $538. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

What is the cheapest time of day to depart on your flight to Illinois?

Our most recent data shows that the best time of day to fly to Illinois is in the evening. Flights from Colorado to Illinois during this time can be as low as $256. Flights at noon are often more expensive with an average ticket price of $537.

What is the cheapest Colorado to Illinois flight route?

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

How far in advance should I book a flight from Colorado to Illinois?

You are more likely to see cheaper flights to Illinois from Colorado when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $292 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Colorado for as low as $238 on momondo.

What cabin class options are available on Colorado to Illinois flights?

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

Can stopping save me money on Colorado to Illinois flights?

You could potentially save up to 1% on your flight if you consider stops on a Colorado to Illinois flight.

Cheap Colorado to Illinois flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Colorado to Illinois

Best Price Found	$140
Fastest flight time	1h 59m
Direct flights	Every day
Airports in Illinois	98 airports

The best one-way flight to Illinois from Colorado in the past 72 hours is $140. The best round-trip flight deal from Colorado to Illinois found on momondo in the last 72 hours is $267.

The fastest flight from Colorado to Illinois takes 1h 59m

Direct flights go from Colorado to Illinois every day.

There are 98 airports in Illinois. From Colorado there are direct flights to Greater Peoria (PIA), Lambert-St Louis (STL), Moline Quad-City (MLI).

Search flight deals

Frequently asked questions about flying from Colorado to Illinois

When did momondo last update prices for flights from Colorado to Illinois?
Prices for flights from Colorado to Illinois are updated daily.
How many operators does momondo search for flights from Colorado to Illinois?
As of August 2026, there are 6 operators available to choose from for flights from Colorado to Illinois.
How old do you have to be to fly from Colorado to Illinois?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Colorado to Illinois.
What documentation or ID do you need to fly to Illinois?
The required travel and health documents for your Illinois trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Illinois. We recommend that you seek guidance from your airline or a reliable third party such as IATA.
What is the most popular plane model from Colorado to Illinois?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from Colorado to Illinois is Airbus A321neo (16.11% of total bookings). The next most popular plane models are Boeing 737-800 (14.93%), Airbus A321-100/200 (12.77%), and Boeing 737 MAX 8 (9.12%).

Best airlines flying from Colorado to Illinois

Compare and see reviews for airlines that fly from Colorado to Illinois with momondo

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $77	Free Cancellation	Rating 5.6 2,713 reviews	Search Frontier flights
Allegiant Air	PriceFrom $91	Free Cancellation	Rating 7.3 679 reviews	Search Allegiant Air flights
JetBlue	PriceFrom $126	Free Cancellation	Rating 7.1 3,031 reviews	Search JetBlue flights
American Airlines	PriceFrom $169	Free Cancellation	Rating 7.1 11,897 reviews	Search American Airlines flights
Southwest	PriceFrom $170	Free Cancellation	Rating 8.0 4,218 reviews	Search Southwest flights
United Airlines	PriceFrom $180	Free Cancellation	Rating 7.4 10,095 reviews	Search United Airlines flights

Why use momondo?

Why should I use momondo to find a flight deal from Colorado to Illinois?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Colorado to Illinois. Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from Colorado to Illinois with flexible booking policies on momondo?

Flights from Colorado to Illinois with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

How can momondo help me find flights from Colorado to Illinois?

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to Illinois from Colorado.

I’m not ready to book a flight from Colorado to Illinois right now. Can momondo alert me if prices change?

If you are not ready to book a flight from Colorado to Illinois now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Illinois and let you know when they change.

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Popular cities in Illinois

Flights to New Yorkfrom $69

Flights to Los Angelesfrom $59

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Flights to Miamifrom $64

Flights to Chicagofrom $62

Flights to San Franciscofrom $60

Flights to Las Vegasfrom $46

Flights to Washington, D.C.from $73

Flights to Bostonfrom $62

Flights to Atlantafrom $46

Flights to Fort Lauderdalefrom $51

Flights to Dallasfrom $53

Cheap flights from Colorado to Illinois from $43

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Colorado to Illinois departing on 9/23. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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Frontier flights from Colorado to Illinois

Our best Frontier deals on Colorado to Illinois flight tickets

American Airlines flights from Colorado to Illinois

Our best American Airlines deals on Colorado to Illinois flight tickets

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How to get the cheapest flight ticket from Colorado to Illinois

What is the cheapest month to fly to Illinois?

What is the cheapest day to depart on your flight to Illinois?

What is the cheapest time of day to depart on your flight to Illinois?

What is the cheapest Colorado to Illinois flight route?

How far in advance should I book a flight from Colorado to Illinois?

What cabin class options are available on Colorado to Illinois flights?

Can stopping save me money on Colorado to Illinois flights?

What is the cheapest airline that flies from Colorado to Illinois?

What airlines fly to Illinois?

How many flights depart from Colorado to Illinois on average per day?

How many flights depart from Colorado to Illinois on average per week?

How long is the flight from Colorado to Illinois?

Cheap Colorado to Illinois flight deals and tips

Best Price Found

Fastest flight time

Direct flights

Airports in Illinois

Frequently asked questions about flying from Colorado to Illinois

Best airlines flying from Colorado to Illinois

Compare and see reviews for airlines that fly from Colorado to Illinois with momondo

Why use momondo?

An easier way to manage your Illinois trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to Illinois

Popular cities in Illinois

Popular flights according to clicks in the last 7 days on momondo

Colorado flight routes

According to popular flight searches on momondo this year

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