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 travellers 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 return 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.

£232 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.

Return

One-way

Last minute

Direct

Recent return flight deals from Illinois to Heathrow

Tue, 10 Nov - Thu, 12 Nov

10:35 - 07:55

MLI

LHR

15h 20m

1 stop

06:50 - 15:07

LHR

MLI

14h 17m

2 stops

£551United Airlines

Tue, 10 Nov - Thu, 12 Nov

14:35 - 11:05

MLI

LHR

14h 30m

2 stops

06:50 - 15:07

LHR

MLI

14h 17m

2 stops

£554United Airlines

Tue, 10 Nov - Thu, 12 Nov

14:35 - 11:05

MLI

LHR

14h 30m

2 stops

06:50 - 15:07

LHR

MLI

14h 17m

2 stops

£555United Airlines

Mon, 28 Sep - Sun, 4 Oct

12:04 - 07:55

BMI

LHR

13h 51m

2 stops

15:15 - 15:45

LHR

BMI

30h 30m

1 stop

£626Virgin Atlantic

Fri, 17 Jul - Tue, 25 Aug

17:43 - 06:45

PIA

LHR

31h 02m

1 stop

06:50 - 22:43

LHR

PIA

21h 53m

2 stops

£641United Airlines

Sat, 10 Oct - Sun, 18 Oct

19:15 - 17:40

ORD

LHR

16h 25m

1 stop

21:05 - 16:10

LHR

ORD

25h 05m

2 stops

£647Scandinavian Airlines

Wed, 11 Nov - Wed, 18 Nov

10:35 - 11:40

MDW

LHR

19h 05m

1 stop

06:30 - 16:25

LHR

MDW

15h 55m

2 stops

£648Virgin Atlantic

Wed, 12 Aug - Wed, 19 Aug

15:45 - 08:05

ORD

LHR

10h 20m

1 stop

13:25 - 19:15

LHR

ORD

11h 50m

1 stop

£648Aer Lingus

Wed, 23 Sep - Wed, 7 Oct

20:50 - 10:50

ORD

LHR

8h 00mdirect

10:20 - 17:50

LHR

ORD

13h 30m

1 stop

£650Finnair

Fri, 16 Oct - Sun, 25 Oct

19:15 - 16:25

ORD

LHR

15h 10m

2 stops

21:05 - 17:45

LHR

ORD

25h 40m

2 stops

£652Scandinavian Airlines

Useful Info

Low season	January
High season	July
Cheapest flight	£232

Best time to beat the crowds (16% less expensive on average)

Most popular time to fly (25% more expensive on average)

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 travellers 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 return 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.

Gatwick

Milton Keynes

Eastbourne

Hounslow

Luton

Southend-on-Sea

Northampton

Swindon

Slough

Winchester

Stansted

Croydon

Folkestone

Poole

Chichester

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Colchester

Maidstone

Salisbury

Crawley

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£232 Find Cheap Flights from Illinois to London Heathrow Airport – Compare and Save

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