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

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

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

As of September 2025, there are 605 flights per week flying from Illinois to Colorado. The most common day of the week flights depart is Mon, with 17% of flights taking off on this day.

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

As of September 2025, 86 flights take off from Illinois and land in Colorado each day. The most common flight departure time for this route is 8:00PM, with 33% of daily flights taking off at noon.

What airlines fly to Colorado?

United Airlines, Frontier and American Airlines 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 34% of people opting to fly with this airline when traveling to Colorado. Keep in mind that there are 6 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 16m on average. Another popular route from Illinois to Colorado is flying from Moline to Denver, which will take roughly 2h 26m. Keep in mind that layovers or delays could extend your travel time.

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 6 operators available for flights from Illinois to Colorado as of September 2025.

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.

$63 Cheap Flights from Illinois to Colorado in 2025/26

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Find the cheapest flights from Illinois to Colorado

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

8:40 pm - 10:10 pmSTL-DEN

2h 30mnonstop

6:00 am - 9:07 amDEN-STL

2h 07mnonstop

$75Frontier

Find Deal

Thu, Oct 30 - Wed, Nov 5

7:52 pm - 9:20 pmSTL-DEN

2h 28mnonstop

6:00 am - 9:07 amDEN-STL

2h 07mnonstop

$81Frontier

Find Deal

Sat, Oct 11 - Mon, Oct 13

3:18 pm - 4:34 pmPIA-DEN

2h 16mnonstop

6:41 pm - 9:32 pmDEN-PIA

1h 51mnonstop

$124Allegiant Air

Find Deal

Mon, Sep 29 - Fri, Oct 3

5:15 am - 6:53 amSTL-DEN

2h 38mnonstop

8:45 pm - 11:58 pmDEN-STL

2h 13mnonstop

$131United Airlines

Find Deal

Thu, Oct 16 - Tue, Oct 21

11:59 am - 1:15 pmPIA-DEN

2h 16mnonstop

6:41 pm - 9:32 pmDEN-PIA

1h 51mnonstop

$140Allegiant Air

Find Deal

Mon, Oct 20 - Fri, Oct 24

9:45 am - 11:30 amORD-COS

2h 45mnonstop

12:13 pm - 3:57 pmCOS-ORD

2h 44mnonstop

$157American Airlines

Find Deal

Sat, Jan 31 - Tue, Feb 3

8:00 am - 9:45 amMDW-DEN

2h 45mnonstop

7:15 pm - 10:35 pmDEN-MDW

2h 20mnonstop

$157Southwest

Find Deal

Wed, Oct 15 - Sat, Oct 18

7:00 am - 1:05 pmORD-COS

7h 05m1 stop

11:35 am - 4:45 pmCOS-ORD

4h 10m1 stop

$177Southwest

Find Deal

Wed, Oct 22 - Wed, Oct 29

9:45 am - 11:30 amORD-COS

2h 45mnonstop

12:13 pm - 3:57 pmCOS-ORD

2h 44mnonstop

$179American Airlines

Find Deal

Fri, Feb 20 - Mon, Feb 23

9:10 am - 11:15 amORD-COS

3h 05mnonstop

1:54 pm - 9:30 pmCOS-ORD

6h 36m1 stop

$189United Airlines

Find Deal

Tue, Oct 7 - Sat, Oct 11

Frontier flights from Illinois to Colorado

Our best Frontier deals on Illinois to Colorado flight tickets

Frontier

Oct 30

STL8:40 pmLambert-St Louis

2h 30m

DEN10:10 pmDenver Intl

Nov 5

DEN6:00 amDenver Intl

2h 07m

STL9:07 amLambert-St Louis

$75

Find similar

Frontier

Oct 11

STL7:52 pmLambert-St Louis

2h 28m

DEN9:20 pmDenver Intl

Oct 13

DEN6:00 amDenver Intl

2h 07m

STL9:07 amLambert-St Louis

$81

Find similar

Frontier

Oct 25

STL7:52 pmLambert-St Louis

2h 28m

DEN9:20 pmDenver Intl

Oct 28

DEN6:00 amDenver Intl

2h 07m

STL9:07 amLambert-St Louis

$82

Find similar

Southwest flights from Illinois to Colorado

Our best Southwest deals on Illinois to Colorado flight tickets

Southwest

Oct 15

MDW8:00 amChicago Midway

2h 45m

DEN9:45 amDenver Intl

Oct 18

DEN7:15 pmDenver Intl

2h 20m

MDW10:35 pmChicago Midway

$157

Find similar

Southwest

Oct 22

ORD7:00 amChicago O'Hare Intl

7h 05m

1 stop

COS1:05 pmColorado Springs

Oct 29

COS11:35 amColorado Springs

4h 10m

1 stop

ORD4:45 pmChicago O'Hare Intl

$177

Find similar

Southwest

Oct 22

ORD2:50 pmChicago O'Hare Intl

7h 20m

1 stop

COS9:10 pmColorado Springs

Oct 29

COS11:35 amColorado Springs

9h 45m

2 stops

ORD10:20 pmChicago O'Hare Intl

$182

Find similar

Fly from

Fly to

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 10/30

8:40 pm-10:10 pm

Nonstop2h 30m

Denver Intl

Wed 11/5

6:00 am-9:07 am

Nonstop2h 07m

$75

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 10/11

7:52 pm-9:20 pm

Nonstop2h 28m

Denver Intl

Mon 10/13

6:00 am-9:07 am

Nonstop2h 07m

$81

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Mon 9/29

3:18 pm-4:34 pm

Nonstop2h 16m

Denver Intl

Fri 10/3

6:41 pm-9:32 pm

Nonstop1h 51m

$124

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 10/16

5:15 am-6:53 am

Nonstop2h 38m

Denver Intl

Tue 10/21

8:45 pm-11:58 pm

Nonstop2h 13m

$131

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Mon 10/20

11:59 am-1:15 pm

Nonstop2h 16m

Denver Intl

Fri 10/24

6:41 pm-9:32 pm

Nonstop1h 51m

$140

ChicagoColorado Springs

ORD - COS

ORDCOS

Chicago O'Hare Intl

Sat 1/31

9:45 am-11:30 am

Nonstop2h 45m

Colorado Springs

Tue 2/3

12:13 pm-3:57 pm

Nonstop2h 44m

$157

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Wed 10/15

8:00 am-9:45 am

Nonstop2h 45m

Denver Intl

Sat 10/18

7:15 pm-10:35 pm

Nonstop2h 20m

$157

ChicagoColorado Springs

ORD - COS

ORDCOS

Chicago O'Hare Intl

Wed 10/22

7:00 am-1:05 pm

1 stop7h 05m

Colorado Springs

Wed 10/29

11:35 am-4:45 pm

1 stop4h 10m

$177

ChicagoColorado Springs

ORD - COS

ORDCOS

Chicago O'Hare Intl

Fri 2/20

9:45 am-11:30 am

Nonstop2h 45m

Colorado Springs

Mon 2/23

12:13 pm-3:57 pm

Nonstop2h 44m

$179

ChicagoColorado Springs

ORD - COS

ORDCOS

Chicago O'Hare Intl

Tue 10/7

9:10 am-11:15 am

Nonstop3h 05m

Colorado Springs

Sat 10/11

1:54 pm-9:30 pm

1 stop6h 36m

$189

Flights are sorted by cheapest round-trip flights first.

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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 November is, on average, the cheapest month to fly to Colorado from Illinois, with most prices found around $160. The month of October is another great option to travel to Colorado, with average flight prices from Illinois averaging around $169.

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 $240. On the other hand, Sunday 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 $293.

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 afternoon when flights can be purchased for as low as $246. At noon is when there is more demand to fly to Colorado, so prices are often more expensive at around $316 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 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 $214 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 $180 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	$101
Fastest flight time	2h 16m
Direct flights	Every day
Airports in Colorado	1 airport

The best one-way flight to Colorado from Illinois in the past 72 hours is $101. The best round-trip flight deal from Illinois to Colorado found on momondo in the last 72 hours is $151.

The fastest flight from Illinois to Colorado takes 2h 16m

Direct flights go from Illinois to Colorado every day.

There is 1 airport near Colorado: Denver Intl (DEN)

Search flight deals

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 6 operators available for flights from Illinois to Colorado as of September 2025.
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 Boeing 737-800, making up 12.20% of the total bookings. Other popular models include Airbus A321neo with 12.00%, Boeing 737 MAX 8 with 10.30%, and Boeing 737-800 Passenger/BBJ2 (winglets) with 8.30%.

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
Frontier	PriceFrom $58	Free Cancellation	Rating 5.8 3,174 reviews	Search Frontier flights
Allegiant Air	PriceFrom $81	Free Cancellation	Rating 7.2 699 reviews	Search Allegiant Air flights
American Airlines	PriceFrom $152	Free Cancellation	Rating 7.2 10,000 reviews	Search American Airlines flights
Southwest	PriceFrom $157	Free Cancellation	Rating 8.0 4,242 reviews	Search Southwest flights
United Airlines	PriceFrom $161	Free Cancellation	Rating 7.4 8,924 reviews	Search United Airlines flights
Delta	PriceFrom $228	Free Cancellation	Rating 7.9 7,957 reviews	Search Delta 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

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.

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Find better results for your trip to Colorado

Popular cities in Colorado

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Cheap flights from Illinois to Colorado from $63

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 11/14. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

Big names and deals

Big names and deals

Filter for what you want

Filter for what you want

Trusted and free

Trusted and free

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Find the cheapest flights from Illinois to Colorado

Cheap round-trip flights

Cheap one-way flights

Cheap last minute flights

Cheap direct flights

Frontier flights from Illinois to Colorado

Our best Frontier deals on Illinois to Colorado flight tickets

Southwest flights from Illinois to Colorado

Our best Southwest 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

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

What is the cheapest month to fly to Colorado?

The month of November is, on average, the cheapest month to fly to Colorado from Illinois, with most prices found around $160. The month of October is another great option to travel to Colorado, with average flight prices from Illinois averaging around $169.

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?

The cheapest time of day to fly to Colorado is in the afternoon when flights can be purchased for as low as $246. At noon is when there is more demand to fly to Colorado, so prices are often more expensive at around $316 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 to Colorado?

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.

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

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

What airlines fly to Colorado?

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

As of September 2025, 86 flights take off from Illinois and land in Colorado each day. The most common flight departure time for this route is 8:00PM, with 33% of daily flights taking off at noon.

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

As of September 2025, there are 605 flights per week flying from Illinois to Colorado. The most common day of the week flights depart is Mon, with 17% of flights taking off on this day.

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

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

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

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

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

What is the most popular plane model 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?

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

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

How can momondo help me find flights 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?

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