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

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

What airlines fly to Colorado?

United Airlines, American Airlines and Frontier are the top three most popular airlines that fly to Colorado from Illinois according to our data. United Airlines is the first choice among our users, with 41% of people opting to fly with this airline when traveling to Colorado. Keep in mind that there are 7 different airlines that fly to Colorado on a routine basis, so you have a few additional options to choose from.

How long is the flight from Illinois to Colorado?

Flight times from Illinois to Colorado vary, but if you’re flying out of Peoria and flying into Denver (one of the most popular routes), then the duration is 2h 19m on average. Another popular route from Illinois to Colorado is flying from Moline to Denver, which will take roughly 2h 27m. Keep in mind that layovers or delays could extend your travel time.

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

As of May 2026, there are 483 flights per week flying from Illinois to Colorado. The most common day of the week flights depart is Sun, with 22% of flights taking off on this day.

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

As of May 2026, 69 flights take off from Illinois and land in Colorado each day. The most common flight departure time for this route is 2:00PM, with 36% of daily flights taking off at noon.

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

Prices for flights from Illinois to Colorado were last updated today.

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

There are 7 operators available for flights from Illinois to Colorado as of May 2026.

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

Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Illinois to Colorado.

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

The travel and health documents you'll need for your trip to Colorado may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Colorado. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

$84 Cheap Flights from Illinois to Colorado in 2026

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Find the cheapest flights from Illinois to Colorado

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

8:08 pm - 9:44 pm

STL

DEN

2h 36mnonstop

4:10 pm - 7:23 pm

DEN

STL

2h 13mnonstop

$142Frontier

Tue, Jun 30 - Wed, Jul 8

8:08 pm - 9:44 pm

STL

DEN

2h 36mnonstop

4:12 pm - 7:23 pm

DEN

STL

2h 11mnonstop

$146Frontier

Tue, Jun 23 - Tue, Jun 30

10:07 am - 11:26 am

PIA

DEN

2h 19mnonstop

2:17 pm - 5:24 pm

DEN

PIA

2h 07mnonstop

$158Allegiant Air

Thu, Aug 20 - Thu, Aug 27

5:23 pm - 6:48 pm

PIA

DEN

2h 25mnonstop

2:17 pm - 5:24 pm

DEN

PIA

2h 07mnonstop

$159Allegiant Air

Thu, Aug 13 - Thu, Aug 20

1:55 pm - 7:50 pm

MDW

DEN

6h 55m

2 stops

1:55 pm - 7:25 pm

DEN

MDW

4h 30m

1 stop

$176Southwest

Wed, Aug 12 - Wed, Aug 19

8:45 pm - 10:20 pm

MDW

DEN

2h 35mnonstop

6:30 am - 9:50 am

DEN

MDW

2h 20mnonstop

$183Southwest

Thu, Aug 13 - Tue, Aug 18

9:05 am - 10:34 am

MLI

DEN

2h 29mnonstop

6:00 am - 12:22 pm

DEN

MLI

5h 22m

1 stop

$279United Airlines

Sat, Aug 22 - Wed, Aug 26

10:16 am - 2:54 pm

STL

COS

5h 38m

1 stop

3:51 pm - 11:42 pm

COS

STL

6h 51m

1 stop

$285American Airlines

Tue, Aug 18 - Thu, Aug 20

10:00 am - 11:52 am

ORD

COS

2h 52mnonstop

12:22 pm - 4:14 pm

COS

ORD

2h 52mnonstop

$287American Airlines

Tue, Jul 7 - Tue, Jul 21

9:15 am - 11:48 am

ORD

MTJ

3h 33mnonstop

12:40 pm - 4:50 pm

MTJ

ORD

3h 10mnonstop

$289United Airlines

Sat, Aug 29 - Sat, Sep 5

Frontier flights from Illinois to Colorado

Our best Frontier deals on Illinois to Colorado flight tickets

Frontier

Jun 30

STL8:08 pmLambert-St Louis

2h 36m

DEN9:44 pmDenver Intl

Jul 8

DEN4:10 pmDenver Intl

2h 13m

STL7:23 pmLambert-St Louis

$142

Frontier

Jun 23

STL8:08 pmLambert-St Louis

2h 36m

DEN9:44 pmDenver Intl

Jun 30

DEN4:12 pmDenver Intl

2h 11m

STL7:23 pmLambert-St Louis

$146

Frontier

Jul 14

STL8:08 pmLambert-St Louis

2h 36m

DEN9:44 pmDenver Intl

Jul 22

DEN4:10 pmDenver Intl

2h 13m

STL7:23 pmLambert-St Louis

$147

Allegiant Air flights from Illinois to Colorado

Our best Allegiant Air deals on Illinois to Colorado flight tickets

Allegiant Air

Aug 20

PIA10:07 amGreater Peoria

2h 19m

DEN11:26 amDenver Intl

Aug 27

DEN2:17 pmDenver Intl

2h 07m

PIA5:24 pmGreater Peoria

$158

Allegiant Air

Aug 13

PIA5:23 pmGreater Peoria

2h 25m

DEN6:48 pmDenver Intl

Aug 20

DEN2:17 pmDenver Intl

2h 07m

PIA5:24 pmGreater Peoria

$159

Allegiant Air

Aug 20

PIA10:07 amGreater Peoria

2h 19m

DEN11:26 amDenver Intl

Aug 27

DEN2:17 pmDenver Intl

2h 07m

PIA5:24 pmGreater Peoria

$165

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 6/30

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Wed 7/8

4:10 pm-7:23 pm

Nonstop2h 13m

$142

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 6/23

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Tue 6/30

4:12 pm-7:23 pm

Nonstop2h 11m

$146

Quickest round-trip

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 8/20

10:07 am-11:26 am

Nonstop2h 19m

Denver Intl

Thu 8/27

2:17 pm-5:24 pm

Nonstop2h 07m

$158

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 8/13

5:23 pm-6:48 pm

Nonstop2h 25m

Denver Intl

Thu 8/20

2:17 pm-5:24 pm

Nonstop2h 07m

$159

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Wed 8/12

1:55 pm-7:50 pm

2 stops6h 55m

Denver Intl

Wed 8/19

1:55 pm-7:25 pm

1 stop4h 30m

$176

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Thu 8/13

8:45 pm-10:20 pm

Nonstop2h 35m

Denver Intl

Tue 8/18

6:30 am-9:50 am

Nonstop2h 20m

$183

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Sat 8/22

9:05 am-10:34 am

Nonstop2h 29m

Denver Intl

Wed 8/26

6:00 am-12:22 pm

1 stop5h 22m

$279

St. LouisColorado Springs

STL - COS

STLCOS

Lambert-St Louis

Tue 8/18

10:16 am-2:54 pm

1 stop5h 38m

Colorado Springs

Thu 8/20

3:51 pm-11:42 pm

1 stop6h 51m

$285

ChicagoColorado Springs

ORD - COS

ORDCOS

Chicago O'Hare Intl

Tue 7/7

10:00 am-11:52 am

Nonstop2h 52m

Colorado Springs

Tue 7/21

12:22 pm-4:14 pm

Nonstop2h 52m

$287

ChicagoMontrose

ORD - MTJ

ORDMTJ

Chicago O'Hare Intl

Sat 8/29

9:15 am-11:48 am

Nonstop3h 33m

Montrose County

Sat 9/5

12:40 pm-4:50 pm

Nonstop3h 10m

$289

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 Illinois to Colorado

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 Colorado?

The month of April is, on average, the cheapest month to fly to Colorado from Illinois, with most prices found around $236. The month of September is another great option to travel to Colorado, with average flight prices from Illinois averaging around $240.

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

The cheapest day to depart from Illinois to Colorado is on a Saturday when prices can be found for as low as $252. On the other hand, Monday is the most expensive day to depart from Illinois because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $323.

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

The cheapest time of day to fly to Colorado is in the evening when flights can be purchased for as low as $238. At noon is when there is more demand to fly to Colorado, so prices are often more expensive at around $306 per ticket.

What is the cheapest Illinois to Colorado flight route?

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

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

You are more likely to see cheaper flights to Colorado from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to Colorado for around $239 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Colorado from Illinois for as low as $197 on momondo.

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

There are 4 cabin classes available to choose from on Illinois to Colorado 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 Illinois to Colorado flights?

No. A direct flight is the cheapest option for a flight between Illinois to Colorado.

Cheap Illinois to Colorado flight deals and tips

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

Best Price Found	$133
Fastest flight time	2h 15m
Direct flights	Every day
Airports in Colorado	87 airports

The best one-way flight to Colorado from Illinois in the past 72 hours is $133. The best round-trip flight deal from Illinois to Colorado found on momondo in the last 72 hours is $246.

The fastest flight from Illinois to Colorado takes 2h 15m

Direct flights go from Illinois to Colorado every day.

There are 87 airports in Colorado. From Illinois there are direct flights to Colorado Springs (COS), Denver Intl (DEN).

Search flight deals

Frequently asked questions about flying from Illinois to Colorado

When did momondo last update prices for flights from Illinois to Colorado?
Prices for flights from Illinois to Colorado were last updated today.
How many operators does momondo search for flights from Illinois to Colorado?
There are 7 operators available for flights from Illinois to Colorado as of May 2026.
How old do you have to be to fly from Illinois to Colorado?
Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Illinois to Colorado.
What documentation or ID do you need to fly to Colorado?
The travel and health documents you'll need for your trip to Colorado may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Colorado. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from Illinois to Colorado?
Based on momondo bookings for flights between Illinois and Colorado, the leading plane model is Airbus A321neo, making up 14.84% of the total bookings. Other popular models include Boeing 737-800 with 14.61%, Airbus A319 with 10.50%, and Boeing 737-900 with 8.60%.

Best airlines flying from Illinois to Colorado

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

Airline	Rating	Free Cancellation	Price
Allegiant Air	PriceFrom $51	Free Cancellation	Rating 7.3 709 reviews	Search Allegiant Air flights
Frontier	PriceFrom $70	Free Cancellation	Rating 5.6 2,929 reviews	Search Frontier flights
Delta	PriceFrom $105	Free Cancellation	Rating 7.9 8,415 reviews	Search Delta flights
JetBlue	PriceFrom $145	Free Cancellation	Rating 7.1 2,984 reviews	Search JetBlue flights
Southwest	PriceFrom $151	Free Cancellation	Rating 8.0 4,262 reviews	Search Southwest flights
American Airlines	PriceFrom $154	Free Cancellation	Rating 7.1 11,646 reviews	Search American Airlines flights
United Airlines	PriceFrom $164	Free Cancellation	Rating 7.4 9,770 reviews	Search United Airlines flights

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Illinois to Colorado. momondo saves you time and could save you money on your trip.

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

Yes. momondo enables you to select and highlight flights to Colorado from Illinois with this policy.

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

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Illinois to Colorado.

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

Yes momondo offers price alerts on flights to Colorado from Illinois. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

An easier way to manage your Colorado trip

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Popular cities in Colorado

Flights to New Yorkfrom $64

Flights to Los Angelesfrom $50

Flights to Orlandofrom $58

Flights to Miamifrom $111

Flights to Chicagofrom $68

Flights to San Franciscofrom $66

Flights to Las Vegasfrom $60

Flights to Washington, D.C.from $56

Flights to Bostonfrom $66

Flights to Atlantafrom $81

Flights to Fort Lauderdalefrom $58

Flights to Dallasfrom $56

Cheap flights from Illinois to Colorado from $84

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Illinois to Colorado departing on 7/29. 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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Big names and deals

Filter for what you want

Filter for what you want

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Find the cheapest flights from Illinois to Colorado

Cheap round-trip flights

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Cheap last minute flights

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Frontier flights from Illinois to Colorado

Our best Frontier deals on Illinois to Colorado flight tickets

Allegiant Air flights from Illinois to Colorado

Our best Allegiant Air deals on Illinois to Colorado flight tickets

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Use the filters below to find and compare flights from Illinois to Colorado that are best for you.

See travel insights to Colorado from

How to get the cheapest flight ticket from Illinois to Colorado

What is the cheapest month to fly to Colorado?

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

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

What is the cheapest Illinois to Colorado flight route?

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

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

Can stopping save me money on Illinois to Colorado flights?

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

What airlines fly to Colorado?

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

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

How long is the flight from Illinois to Colorado?

Cheap Illinois to Colorado flight deals and tips

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

Best Price Found

Fastest flight time

Direct flights

Airports in Colorado

Frequently asked questions about flying from Illinois to Colorado

Best airlines flying from Illinois to Colorado

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

Why use momondo?

An easier way to manage your Colorado 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 Colorado

Popular cities in Colorado

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

Illinois flight routes

According to popular flight searches on momondo this year

Colorado flight routes

According to popular flight searches on momondo this year

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