How does KAYAK find such low prices on flights from Illinois to London Heathrow Airport?

KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Illinois to London Heathrow Airport. Visit our flight page for the latest deals!>/a>

How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to London Heathrow Airport?

KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from Illinois is likely to change within 7 days, so travelers know whether to wait or book now. Visit our flight page for the latest deals!>/a>

What is the Hacker Fare option on flights from Illinois to London Heathrow Airport?

Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London Heathrow Airport with an airline and back to Illinois with another airline. Visit our flight page for the latest deals!>/a>

What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to London Heathrow Airport?

Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London Heathrow Airport from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best. Visit our flight page for the latest deals!>/a>

$318 CHEAP FLIGHTS from Illinois to London Heathrow (LHR)

LHR

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Cheap Flights from Illinois to Heathrow

Discover the best prices for you by selecting your travel dates on KAYAK.

Round-trip

One-way

Last minute

Direct

Recent round-trip flight deals from Illinois to Heathrow

Mon, Nov 16 - Thu, Nov 19

8:45 pm - 7:55 am

BMI

LHR

29h 10m

1 stop

6:50 am - 5:52 pm

LHR

BMI

17h 02m

2 stops

$737United Airlines

Mon, Sep 28 - Sun, Oct 4

12:08 pm - 7:15 am

BMI

LHR

13h 07m

1 stop

2:45 pm - 3:39 pm

LHR

BMI

30h 54m

2 stops

$810Virgin Atlantic

Tue, Nov 17 - Tue, Nov 24

1:33 pm - 10:25 am

CMI

LHR

14h 52m

1 stop

6:05 am - 7:25 pm

LHR

CMI

19h 20m

2 stops

$862Iberia

Tue, Nov 17 - Tue, Nov 24

1:33 pm - 2:20 pm

CMI

LHR

18h 47m

2 stops

6:05 am - 7:25 pm

LHR

CMI

19h 20m

2 stops

$870Iberia

Wed, Sep 23 - Wed, Sep 30

6:00 am - 6:25 am

MLI

LHR

18h 25m

1 stop

6:30 am - 4:29 pm

LHR

MLI

15h 59m

2 stops

$876KLM

Wed, Sep 23 - Wed, Sep 30

5:10 pm - 1:15 pm

MLI

LHR

14h 05m

1 stop

6:30 am - 4:29 pm

LHR

MLI

15h 59m

2 stops

$877KLM

Sun, Aug 23 - Tue, Sep 15

12:09 pm - 6:25 am

BMI

LHR

12h 16m

1 stop

6:30 am - 10:24 pm

LHR

BMI

21h 54m

2 stops

$877Delta

Sun, Aug 30 - Tue, Sep 8

4:30 pm - 6:45 am

ORD

LHR

8h 15mnonstop

11:05 am - 2:10 pm

LHR

ORD

9h 05mnonstop

$880Austrian Airlines

Wed, Sep 23 - Wed, Sep 30

6:00 am - 6:45 am

MLI

LHR

18h 45m

2 stops

9:55 am - 10:24 pm

LHR

MLI

18h 29m

2 stops

$881Delta

Thu, Sep 3 - Mon, Sep 7

4:30 pm - 6:45 am

ORD

LHR

8h 15mnonstop

7:30 pm - 1:20 pm

LHR

ORD

23h 50m

1 stop

$888Austrian Airlines

Useful Info

Low season	January
High season	July
Cheapest flight	$318

Best time to beat the crowds with an average 15% drop in price.

Most popular time to fly with an average 16% increase in price.

Flight from St. Louis to London Heathrow Airport

Verified travelerFlew with British Airways

ORD

LHR

Mar 2026

Take early morning flights to adjust to weather-related delays.

Verified travelerFlew with British Airways

ORD

LHR

Jun 2025

Get a wheel chair if you have difficulty walking

JoeFlew with Iberia

ORD

LHR

Apr 2025

Get there early. Nice airport options while you wait.

Verified travelerFlew with Iberia

ORD

LHR

May 2025

Get to the airport early so you’re relaxed. Con yourself into believing it’s bedtime and try to sleep so that you can keep going all day when you get there. If you can afford more comfy seats it might be worth it - though I always have the cheap ones so I can’t say for sure. Try very hard not to. sit in the middle. I’m small and the guy next to me played games all night and didn’t care that he continually ( with every move) jabbed me with his arm. This was my first flight with Cheap Flights and it was far less convenient than other times I’ve flown overseas.

DinaFlew with United Airlines

ORD

LHR

Jan 2025

Anticipate delays, prepare for long walks through Heathrow to baggage claim or for connections.

KariFlew with British Airways

ORD

LHR

May 2024

Always check to confirm your assistance is in system. No wheelchair waiting for me in London. Had no clue about airport or how to get around. Got lost easy

AaronFlew with American Airlines

ORD

LHR

Dec 2023

Find a flight where you are allowed to choose your seats before the day of boarding for anything international.

How does KAYAK find such low prices on flights from Illinois to London Heathrow Airport?
KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Illinois to London Heathrow Airport.
How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to London Heathrow Airport?
KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from Illinois is likely to change within 7 days, so travelers know whether to wait or book now.
What is the Hacker Fare option on flights from Illinois to London Heathrow Airport?
Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London Heathrow Airport with an airline and back to Illinois with another airline.
What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to London Heathrow Airport?
Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London Heathrow Airport from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Hounslow

Slough

Hayes

Richmond

Wembley

Luton

Salisbury

Crawley

Ilford

Watford

Eastbourne

Bedford

Swindon

Colchester

Northampton

Twickenham

Guildford

Ipswich

Kingston upon Thames

St. Albans

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London Heathrow Airport (LHR)

LHR

$318 Find Cheap Flights from Illinois to London Heathrow Airport

KAYAK searches hundreds of travel sites at once for deals on flights to London Heathrow Airport

Cheap Flights from Illinois to Heathrow

Recent round-trip flight deals from Illinois to Heathrow

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Good to know

Flights from Illinois to Heathrow: the best tips from KAYAK users

FAQs for booking Illinois to London Heathrow Airport flights

How does KAYAK find such low prices on flights from Illinois to London Heathrow Airport?

KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Illinois to London Heathrow Airport.

How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to London Heathrow Airport?

KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

What is the Hacker Fare option on flights from Illinois to London Heathrow Airport?

Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London Heathrow Airport with an airline and back to Illinois with another airline.

What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to London Heathrow Airport?

Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London Heathrow Airport from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Traveling to a place near Heathrow?

Everything you need to know for your flight to Heathrow

Information on your arrival and departure airports

Cabin class types available on flights to Heathrow

Complete your trip to Heathrow with a hotel stay or car rental

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