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.

$299 CHEAP FLIGHTS from Illinois to London Heathrow (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

Sun, Oct 4 - Tue, Oct 13

5:10 pm - 10:50 amSTL Lambert-St Louis-LHR London Heathrow

11h 40m1 stop Chicago O'Hare Intl

9:45 am - 12:19 amLHR London Heathrow-STL Lambert-St Louis

20h 34m1 stop Chicago O'Hare Intl

$710Finnair

Wed, Oct 14 - Wed, Oct 21

12:10 pm - 6:30 amSTL Lambert-St Louis-LHR London Heathrow

12h 20m1 stop Montreal Pierre Elliott Trudeau Intl

8:40 am - 6:41 pmLHR London Heathrow-STL Lambert-St Louis

16h 01m2 stops Zurich Montreal Pierre Elliott Trudeau Intl

$717Air Canada

Wed, Oct 14 - Wed, Oct 21

8:55 am - 6:30 amSTL Lambert-St Louis-LHR London Heathrow

15h 35m2 stops Toronto Pearson Intl Montreal Pierre Elliott Trudeau Intl

8:40 am - 6:41 pmLHR London Heathrow-STL Lambert-St Louis

16h 01m2 stops Zurich Montreal Pierre Elliott Trudeau Intl

$724Air Canada

Sun, Oct 4 - Tue, Oct 13

5:10 pm - 10:50 amSTL Lambert-St Louis-LHR London Heathrow

11h 40m1 stop Chicago O'Hare Intl

9:45 am - 12:19 amLHR London Heathrow-STL Lambert-St Louis

20h 34m1 stop Chicago O'Hare Intl

$726Finnair

Wed, Oct 7 - Sun, Oct 11

2:20 pm - 4:25 pmORD Chicago O'Hare Intl-LHR London Heathrow

20h 05m1 stop Zurich

6:00 am - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 55m1 stop Zurich

$734SWISS

Tue, Nov 3 - Tue, Nov 10

1:27 pm - 7:45 amMDW Chicago Midway-LHR London Heathrow

12h 18m1 stop Detroit Metropolitan Wayne County

11:20 am - 6:04 pmLHR London Heathrow-MDW Chicago Midway

12h 44m1 stop Detroit Metropolitan Wayne County

$734Air France

Tue, Oct 20 - Fri, Oct 30

1:17 pm - 6:55 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 38m1 stop Charlotte Douglas

4:30 pm - 8:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 50mnonstop

$735American Airlines

Mon, Oct 12 - Fri, Oct 23

5:00 pm - 10:05 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 05m1 stop Pittsburgh

9:45 am - 12:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$735American Airlines

Thu, Oct 1 - Mon, Oct 5

2:20 pm - 7:55 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 35m1 stop Zurich

6:40 pm - 12:35 pmLHR London Heathrow-ORD Chicago O'Hare Intl

23h 55m1 stop Zurich

$736SWISS

Tue, Nov 3 - Tue, Nov 24

1:00 pm - 11:40 amMLI Moline Quad-City-LHR London Heathrow

16h 40m1 stop Atlanta Hartsfield-Jackson

6:30 am - 4:33 pmLHR London Heathrow-MLI Moline Quad-City

16h 03m2 stops Amsterdam Schiphol Atlanta Hartsfield-Jackson

$749KLM

Recent last minute flight deals from Illinois to Heathrow

Wed, Sep 23 - Wed, Sep 30

6:57 pm - 12:10 pmORD Chicago O'Hare Intl-LHR London Heathrow

11h 13m1 stop Charlotte Douglas

11:10 am - 1:50 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mnonstop

$735American Airlines

Wed, Sep 23 - Wed, Oct 7

3:50 pm - 9:35 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 45m1 stop Boston Logan Intl

2:45 pm - 5:35 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 50mnonstop

$735American Airlines

Mon, Sep 21 - Tue, Sep 29

1:19 pm - 7:10 amMDW Chicago Midway-LHR London Heathrow

11h 51m1 stop Detroit Metropolitan Wayne County

9:20 am - 4:15 pmLHR London Heathrow-MDW Chicago Midway

12h 55m1 stop Atlanta Hartsfield-Jackson

$736Delta

Wed, Sep 23 - Wed, Sep 30

1:19 pm - 7:10 amMDW Chicago Midway-LHR London Heathrow

11h 51m1 stop Detroit Metropolitan Wayne County

6:30 am - 6:19 pmLHR London Heathrow-MDW Chicago Midway

17h 49m2 stops Amsterdam Schiphol Minneapolis St Paul

$737Virgin Atlantic

Wed, Sep 23 - Wed, Oct 7

1:19 pm - 7:10 amMDW Chicago Midway-LHR London Heathrow

11h 51m1 stop Detroit Metropolitan Wayne County

6:30 am - 6:00 pmLHR London Heathrow-MDW Chicago Midway

17h 30m2 stops Amsterdam Schiphol Detroit Metropolitan Wayne County

$738Delta

Mon, Sep 21 - Tue, Sep 29

1:19 pm - 7:10 amMDW Chicago Midway-LHR London Heathrow

11h 51m1 stop Detroit Metropolitan Wayne County

6:15 am - 4:15 pmLHR London Heathrow-MDW Chicago Midway

16h 00m2 stops Paris Charles de Gaulle Atlanta Hartsfield-Jackson

$738Virgin Atlantic

Wed, Sep 23 - Tue, Sep 29

11:05 am - 6:30 amORD Chicago O'Hare Intl-LHR London Heathrow

13h 25m1 stop Montreal Pierre Elliott Trudeau Intl

2:05 pm - 8:12 pmLHR London Heathrow-ORD Chicago O'Hare Intl

12h 07m1 stop Montreal Pierre Elliott Trudeau Intl

$738Air Canada

Wed, Sep 23 - Thu, Oct 15

7:05 pm - 9:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

3:15 pm - 6:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 00mnonstop

$740British Airways

Wed, Sep 23 - Wed, Oct 14

7:05 pm - 9:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

1:10 pm - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$740British Airways

Wed, Sep 23 - Wed, Sep 30

2:40 pm - 6:35 amSTL Lambert-St Louis-LHR London Heathrow

9h 55m1 stop Toronto Pearson Intl

5:40 pm - 12:13 pmLHR London Heathrow-STL Lambert-St Louis

24h 33m2 stops Toronto Pearson Intl Chicago O'Hare Intl

$772Air Canada

Recent direct flight deals from Illinois to Heathrow

Wed, Dec 30 - Wed, Jan 13

5:45 pm - 7:55 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

1:35 pm - 4:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$735United Airlines

Tue, Sep 29 - Tue, Feb 2

4:25 pm - 6:45 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 20mnonstop

7:40 am - 10:45 amLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$735United Airlines

Wed, Nov 25 - Wed, Dec 2

6:30 pm - 8:35 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 05mnonstop

3:40 pm - 6:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$738Iberia

Wed, Nov 25 - Tue, Dec 1

9:50 pm - 11:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$738Iberia

Wed, Oct 14 - Tue, Oct 20

5:00 pm - 6:50 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 50mnonstop

1:10 pm - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$738British Airways

Tue, Oct 13 - Thu, Oct 22

7:05 pm - 9:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

1:10 pm - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$738British Airways

Sun, Feb 7 - Thu, Feb 25

6:50 pm - 8:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

4:30 pm - 7:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$740American Airlines

Mon, Jan 25 - Wed, Feb 3

5:10 pm - 6:55 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

12:35 pm - 3:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 55mnonstop

$740American Airlines

Tue, Nov 17 - Fri, Nov 27

9:50 pm - 12:00 pmORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

7:40 am - 10:45 amLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$750Austrian Airlines

Wed, Dec 30 - Wed, Jan 13

3:45 pm - 5:55 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

7:40 am - 10:45 amLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$828Austrian Airlines

Useful Info

Low season	January
High season	July
Cheapest flight	$299

Best time to beat the crowds with an average 23% drop in price.

Most popular time to fly with an average 23% increase in price.

Flight from Chicago O'Hare Airport to London Heathrow Airport

JKFlew with American Airlines-Sep 2026

Ask ahead of time, if the aircraft can provide AC and/or oxygen to passengers after boarding.

Verified travelerFlew with British Airways-Mar 2026

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

Verified travelerFlew with British Airways-Jun 2025

Get a wheel chair if you have difficulty walking

JoeFlew with Iberia-Apr 2025

Get there early. Nice airport options while you wait.

Verified travelerFlew with Iberia-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-Jan 2025

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

KariFlew with British Airways-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-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

Salisbury

Luton

Eastbourne

Ilford

Crawley

Guildford

Swindon

Colchester

Northampton

Ipswich

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Kingston upon Thames

Watford

Newbury

Twickenham

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$299 Find Cheap Flights from Illinois to London Heathrow Airport - Compare and Save

Cheap Flights from Illinois to Heathrow

Recent round-trip flight deals from Illinois to Heathrow

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

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