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

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.

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

KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London 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?

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 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?

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 from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

£168 CHEAP FLIGHTS from Illinois to London

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Cheap Flights from Illinois to London

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 London

Wed, 2 Dec - Tue, 8 Dec

18:05 - 06:50STL Lambert-St Louis-LGW London Gatwick

30h 45m1 stop Orlando

09:35 - 00:41LGW London Gatwick-STL Lambert-St Louis

21h 06m1 stop Orlando

£404Multiple Airlines

Wed, 2 Dec - Tue, 8 Dec

14:59 - 06:50STL Lambert-St Louis-LGW London Gatwick

33h 51m2 stops Atlanta Hartsfield-Jackson Orlando

09:35 - 00:41LGW London Gatwick-STL Lambert-St Louis

21h 06m1 stop Orlando

£462Multiple Airlines

Mon, 4 Jan - Sun, 28 Feb

18:30 - 19:30ORD Chicago O'Hare Intl-LHR London Heathrow

19h 00m1 stop Reykjavik Keflavik Intl

20:35 - 17:20LHR London Heathrow-ORD Chicago O'Hare Intl

26h 45m1 stop Reykjavik Keflavik Intl

£522Icelandair

Sat, 12 Dec - Sat, 26 Dec

18:30 - 19:30ORD Chicago O'Hare Intl-LHR London Heathrow

19h 00m1 stop Reykjavik Keflavik Intl

20:35 - 17:20LHR London Heathrow-ORD Chicago O'Hare Intl

26h 45m1 stop Reykjavik Keflavik Intl

£522Icelandair

Wed, 25 Nov - Mon, 30 Nov

18:30 - 08:35ORD Chicago O'Hare Intl-LHR London Heathrow

8h 05mdirect

15:00 - 15:10LHR London Heathrow-ORD Chicago O'Hare Intl

30h 10m1 stop Madrid Barajas

£531Iberia

Wed, 10 Mar - Tue, 16 Mar

17:10 - 06:55ORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mdirect

11:00 - 14:45LHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mdirect

£531Iberia

Wed, 6 Jan - Wed, 20 Jan

17:10 - 06:55ORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mdirect

16:30 - 19:15LHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mdirect

£531British Airways

Wed, 7 Oct - Thu, 28 Jan

22:30 - 12:15ORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mdirect

07:30 - 14:55LHR London Heathrow-ORD Chicago O'Hare Intl

13h 25m1 stop Madrid Barajas

£531British Airways

Wed, 28 Oct - Tue, 3 Nov

19:35 - 08:35ORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mdirect

08:20 - 15:50LHR London Heathrow-ORD Chicago O'Hare Intl

13h 30m1 stop Paris Charles de Gaulle

£535American Airlines

Wed, 30 Sep - Wed, 4 Nov

17:00 - 06:50ORD Chicago O'Hare Intl-LHR London Heathrow

7h 50mdirect

08:20 - 15:50LHR London Heathrow-ORD Chicago O'Hare Intl

13h 30m1 stop Paris Charles de Gaulle

£535American Airlines

Recent last minute flight deals from Illinois to London

Tue, 15 Sep - Thu, 1 Oct

13:29 - 06:45ORD Chicago O'Hare Intl-LHR London Heathrow

11h 16m1 stop New York John F Kennedy Intl

08:55 - 15:10LHR London Heathrow-ORD Chicago O'Hare Intl

12h 15m1 stop Paris Charles de Gaulle

£539Delta

Wed, 16 Sep - Thu, 24 Sep

10:25 - 07:15ORD Chicago O'Hare Intl-LHR London Heathrow

14h 50m1 stop New York John F Kennedy Intl

06:15 - 15:10LHR London Heathrow-ORD Chicago O'Hare Intl

14h 55m1 stop Paris Charles de Gaulle

£539Delta

Wed, 16 Sep - Wed, 23 Sep

15:50 - 08:00ORD Chicago O'Hare Intl-LHR London Heathrow

10h 10m1 stop Boston Logan Intl

11:10 - 13:50LHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mdirect

£539American Airlines

Tue, 15 Sep - Thu, 1 Oct

21:15 - 11:15ORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mdirect

09:45 - 12:25LHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mdirect

£539British Airways

Tue, 15 Sep - Tue, 22 Sep

21:15 - 11:15ORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mdirect

09:45 - 12:25LHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mdirect

£539British Airways

Tue, 15 Sep - Thu, 1 Oct

21:15 - 11:15ORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mdirect

12:15 - 14:55LHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mdirect

£540American Airlines

Tue, 15 Sep - Tue, 22 Sep

13:35 - 06:25ORD Chicago O'Hare Intl-LHR London Heathrow

10h 50m1 stop New York John F Kennedy Intl

07:50 - 16:00LHR London Heathrow-ORD Chicago O'Hare Intl

14h 10m1 stop Madrid Barajas

£540Iberia

Wed, 16 Sep - Wed, 23 Sep

15:50 - 08:00ORD Chicago O'Hare Intl-LHR London Heathrow

10h 10m1 stop Boston Logan Intl

12:15 - 14:55LHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mdirect

£541Iberia

Wed, 16 Sep - Wed, 23 Sep

08:45 - 10:00ORD Chicago O'Hare Intl-LHR London Heathrow

19h 15m1 stop Montreal Pierre Elliott Trudeau Intl

08:00 - 11:10LHR London Heathrow-ORD Chicago O'Hare Intl

9h 10mdirect

£543United Airlines

Wed, 16 Sep - Thu, 24 Sep

08:45 - 06:30ORD Chicago O'Hare Intl-LHR London Heathrow

15h 45m1 stop Montreal Pierre Elliott Trudeau Intl

11:05 - 14:10LHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mdirect

£543United Airlines

Useful Info

Low season	February
High season	March
Cheapest flight	£168

Best time to beat the crowds (20% less expensive on average)

Most popular time to fly and prices are also 17% lower on average.

Flight from St. Louis to London Gatwick Airport

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?
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.
How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to London?
KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London 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?
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 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?
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 from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Gatwick

Eastbourne

Milton Keynes

Hounslow

Luton

Southend-on-Sea

Newport

Folkestone

Winchester

Slough

Croydon

Stansted

Colchester

Chichester

Crawley

Maidstone

Chelmsford

Hastings

Bedford

Richmond

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£168 Find Cheap Flights from Illinois to London – Compare and Save

Cheap Flights from Illinois to London

Recent return flight deals from Illinois to London

Recent one-way flight deals from Illinois to London

Recent last minute flight deals from Illinois to London

Recent direct flight deals from Illinois to London

Good to know - Cheap tickets from Illinois to London

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High season

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

FAQs for booking flights from Illinois to London

Travelling to a place near London?

More options for your flight to London

Complete your trip to London with a hotel stay or car hire

Cabin class types available on flights to Illinois

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