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 travellers 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 return 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>

£247 CHEAP FLIGHTS from Illinois to London Heathrow (LHR)

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

...and more

Travellers love KAYAK

41,299,237 searches in the past 7 days on KAYAK

Save 25% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Cheapest return fare

£385

Overall average: £485

Icelandair

Tue 7/4Tue 12/5

ORD - LHR • 1 stop

Cheapest direct flights

£440

Typical prices: £485-£644

Finnair

Sun 22/2Tue 3/3

ORD - LHR • Direct

Start a new search

KAYAK searches hundreds of sites at once to find you the best travel deals.

We hope you love your trip to Heathrow!

Flight Deals

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 return flight deals from Illinois to Heathrow

Tue, 7 Apr - Tue, 12 May

19:25 - 11:55

ORD

LHR

10h 30m

1 stop

21:25 - 18:15

LHR

ORD

26h 50m

1 stop

£385Icelandair

Fri, 24 Apr - Mon, 27 Apr

19:15 - 09:35

ORD

LHR

32h 20m

2 stops

06:40 - 16:10

LHR

ORD

15h 30m

1 stop

£386Scandinavian Airlines

Mon, 9 Mar - Mon, 16 Mar

06:00 - 07:50

MLI

LHR

20h 50m

1 stop

06:30 - 22:30

LHR

MLI

21h 00m

2 stops

£465Delta

Mon, 9 Mar - Mon, 16 Mar

06:00 - 07:05

MLI

LHR

20h 05m

2 stops

08:40 - 22:30

LHR

MLI

18h 50m

2 stops

£468Delta

Wed, 25 Mar - Wed, 1 Apr

06:25 - 07:10

STL

LHR

19h 45m

2 stops

06:30 - 13:25

LHR

STL

12h 55m

1 stop

£469Multiple Airlines

Mon, 23 Feb - Wed, 4 Mar

13:11 - 07:55

STL

LHR

12h 44m

1 stop

06:30 - 13:55

LHR

STL

13h 25m

1 stop

£469United Airlines

Wed, 22 Apr - Wed, 29 Apr

15:30 - 18:40

STL

LHR

21h 10m

1 stop

10:50 - 23:57

LHR

STL

19h 07m

2 stops

£471Lufthansa

Mon, 9 Mar - Wed, 18 Mar

16:05 - 08:30

STL

LHR

11h 25m

1 stop

08:45 - 23:51

LHR

STL

20h 06m

2 stops

£471Multiple Airlines

Tue, 3 Mar - Tue, 10 Mar

09:55 - 07:10

STL

LHR

15h 15m

2 stops

11:10 - 22:59

LHR

STL

16h 49m

2 stops

£474United Airlines

Mon, 30 Mar - Fri, 10 Apr

18:35 - 16:40

STL

LHR

16h 05m

2 stops

06:30 - 13:25

LHR

STL

12h 55m

1 stop

£474Lufthansa

Useful Info

Low season	January
High season	July
Cheapest flight	£247

Best time to beat the crowds (6% less expensive on average)

Most popular time to fly (8% more expensive on average)

Flight from St. Louis to London Heathrow Airport

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

Swindon

Northampton

Slough

Winchester

Croydon

Stansted

Folkestone

Poole

Maidstone

Chichester

Salisbury

Colchester

Chelmsford

Crawley

Everything you need to know for your flight to Heathrow

Airports

Cabin class

Complete your trip

Direct flights

Flights to other cities

Origins

Other airports

Return flight deals

Information on your arrival and departure airports

London Heathrow Airport (LHR)

£242 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

Everything you should know

Cheap Flights from Illinois to Heathrow

Recent return flight deals from Illinois to Heathrow

Recent one-way flight deals from Illinois to Heathrow

Recent last minute flight deals from Illinois to Heathrow

Recent direct flight deals from Illinois to Heathrow

Good to know - Cheap tickets from Illinois to London Heathrow Airport

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 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.

Travelling 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 hire

Find direct flights for Heathrow

Flights to other popular destinations

Flights from domestic origins to Illinois

Choose which airport to fly into in London

Find deals for your return flight