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Cheap flights from Illinois to London Heathrow Airport from £228

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/10. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — LHR
16 Sep — 23 Sep1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Illinois to Heathrow

Enter your travel dates to find the best prices.

Cheapest flights from Illinois to Heathrow
Explore the most affordable flight options available from Illinois to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 17 August 2026.

Fri 25/919:15 -
2 stops17h 15m
Sun 27/917:00 -
1 stop29h 10m
Deal found 13/8£493
Sun 15/1119:15 -
1 stop32h 05m
Wed 18/1106:40 -
2 stops16h 05m
Deal found 15/8£495
Sat 14/1119:15 -
1 stop32h 05m
Mon 16/1121:05 -
2 stops25h 40m
Deal found 12/8£496
Mon 28/909:38 -
1 stop14h 52m
Tue 6/1007:40 -
1 stop12h 20m
Deal found 13/8£497
Fri 13/1119:15 -
2 stops31h 40m
Sun 15/1119:50 -
2 stops26h 55m
Deal found 13/8£500
Sat 3/1019:15 -
2 stops15h 45m
Mon 5/1006:40 -
1 stop15h 30m
Deal found 14/8£503
Sun 15/1117:22 -
1 stop32h 33m
Wed 18/1106:50 -
2 stops33h 18m
Deal found 13/8£544
Sun 6/1216:05 -
2 stops33h 05m
Wed 9/1206:35 -
2 stops38h 51m
Deal found 16/8£550
Sun 6/1216:30 -
1 stop35h 10m
Wed 9/1207:30 -
2 stops17h 59m
Deal found 15/8£557
Wed 11/1115:40 -
1 stop17h 05m
Fri 13/1107:40 -
2 stops21h 44m
Deal found 12/8£561
Sun 6/1210:35 -
2 stops17h 30m
Tue 8/1207:40 -
1 stop21h 24m
Deal found 13/8£561
Tue 10/1111:29 -
2 stops17h 16m
Thu 12/1107:40 -
2 stops20h 44m
Deal found 12/8£564

Find flight deals from Illinois to Heathrow

Keep the following information in mind while searching for Illinois to Heathrow flight deals. Data was last updated 17 August 2026.

Round-trip from

£493

One-way from

£228

Popular in

June

Cheapest in

February

Average price

£646

Good round-trip deal

£686 or less

Good one-way deal

£412 or less
Scandinavian Airlines
  • Scandinavian Airlines
  • 25/9-27/9
  • 3 total stops
  • 46h 25m total
  • Illinois to London
Search Deals
Icelandair
  • Icelandair
  • 11/10
  • 1 total stop
  • 31h 30m total
  • Illinois to London
Search Deals
Highest demand for flights based on searches. 24% potential increase in price (£149 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease (£28 potential savings vs. average return price).
Search Deals
Average for round-trip flights in August 2026
Search Deals
Price to beat on a round-trip flight from Illinois to London Heathrow.
Search Deals
Price to beat on a one-way flight from Illinois to London Heathrow.
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from Illinois to Heathrow that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 17 August 2026.
Use the filters below to find and compare flights from Illinois to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

PeoriaLondon

PIA Greater Peoria - LHR London Heathrow

PIALHR

Greater Peoria

Sun 15/11

17:22-07:55

1 stop32h 33m

London Heathrow

Wed 18/11

06:50-10:08

2 stops33h 18m

£544

MolineLondon

MLI Moline Quad-City - LHR London Heathrow

MLILHR

Moline Quad-City

Sun 6/12

13:00-07:55

1 stop12h 55m

London Heathrow

Tue 8/12

06:35-17:41

2 stops17h 06m

£597

St. LouisLondon

STL Lambert-St Louis - LHR London Heathrow

STLLHR

Lambert-St Louis

Tue 24/11

10:00-09:00

1 stop17h 00m

London Heathrow

Tue 8/12

10:00-21:33

2 stops17h 33m

£640

St. LouisLondon

STL Lambert-St Louis - LHR London Heathrow

STLLHR

Lambert-St Louis

Tue 24/11

09:45-06:50

2 stops15h 05m

London Heathrow

Tue 8/12

10:00-20:51

2 stops16h 51m

£644

ChicagoLondon

ORD Chicago O'Hare Intl - LHR London Heathrow

ORDLHR

Chicago O'Hare Intl

Sun 27/9

18:35-09:00

Nonstop8h 25m

London Heathrow

Mon 5/10

12:10-12:35

1 stop30h 25m

£644

MolineLondon

MLI Moline Quad-City - LHR London Heathrow

MLILHR

Moline Quad-City

Tue 9/2

14:26-12:00

1 stop15h 34m

London Heathrow

Tue 16/2

06:50-17:41

2 stops16h 51m

£647

PeoriaLondon

PIA Greater Peoria - LHR London Heathrow

PIALHR

Greater Peoria

Tue 9/2

13:20-05:55

1 stop10h 35m

London Heathrow

Tue 16/2

06:50-16:31

2 stops15h 41m

£647

St. LouisLondon

STL Lambert-St Louis - LHR London Heathrow

STLLHR

Lambert-St Louis

Tue 24/11

18:50-07:55

1 stop31h 05m

London Heathrow

Tue 8/12

18:00-15:26

1 stop27h 26m

£648

St. LouisLondon

STL Lambert-St Louis - LHR London Heathrow

STLLHR

Lambert-St Louis

Wed 13/1

11:51-08:05

2 stops14h 14m

London Heathrow

Tue 19/1

10:00-20:37

2 stops16h 37m

£651

ChicagoLondon

MDW Chicago Midway - LHR London Heathrow

MDWLHR

Chicago Midway

Tue 27/10

12:45-06:25

1 stop12h 40m

London Heathrow

Tue 10/11

06:30-16:39

2 stops16h 09m

£654

Flights are sorted by cheapest return flights first.

Deals found on 13/8

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Illinois to Heathrow

Have a flexible travel schedule? Discover the best time to fly to Heathrow from Illinois with our price prediction graph.
Estimated return price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Illinois to London Heathrow Airport

What is the cheapest month to book a flight from Illinois to London Heathrow Airport?

Currently, January is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £480). Flying from Illinois to London Heathrow Airport in June is currently the most expensive (average of £1,023). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from IL to LHR?

Find hourly flight availability from Illinois to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 17 August 2026.

When flying from Illinois to London Heathrow Airport, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from Illinois to London Heathrow Airport

Explore weekly flight availability from Illinois to Heathrow. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 17 August 2026.

The most flights from USIL to LHR are scheduled on a Friday (54 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (41 on average).

How much does it cost for a return flight from Illinois to London Heathrow Airport?

Airfare is below average for this route at the moment.
Illinois to London Heathrow Airport flights typically cost between £547 and £798 in September.
The cheapest return price found within the last 5 days was £493 on Scandinavian Airlines (25 Sept–27 Sept).

How far ahead should I book a flight from Illinois to London Heathrow Airport?

The price you pay for your flight from Illinois to London Heathrow Airport may vary depending on when you book. For the best chance of a lower fare, look to book 58 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Related info for your journey

Find useful and relevant information for your journey from Illinois to Heathrow. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Illinois to London Heathrow Airport?

    For as low as £644, United Airlines can have you in London Heathrow Airport from Illinois in 15h 05m. The distance from Illinois to London Heathrow Airport is about 4186 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines to fly from Illinois to London Heathrow Airport one-way?

    The cheapest airline one-way is TAP AIR PORTUGAL, with whom users have recently found tickets for as low as £163. However, be on the lookout for offers from Lufthansa and British Airways, as they are both options that can get you from Illinois to London Heathrow Airport for a low price.

  • What are the most popular routes from Illinois to London Heathrow Airport?

    The most popular route from Illinois to London Heathrow Airport is Chicago O'Hare Intl - London Heathrow. You may also consider Chicago Midway - London Heathrow or Lambert-St Louis - London Heathrow.

  • What are the most reliable airlines from Illinois to London Heathrow Airport?

    No one likes to see their flight delayed. When booking a flight from Illinois to London Heathrow Airport consider choosing Air Canada (62%), Austrian Airlines (62%) or United Airlines (62%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Illinois to London Heathrow Airport?

    On average you can expect to pay £1,354 for a flight from Illinois to London Heathrow Airport. The cheapest flight overall is £246 while the most popular route, (Chicago O'Hare Intl - London Heathrow) is currently priced at £495.

  • Can I find deals for flights from Illinois to Heathrow that include hotel bookings?

    Yes. In addition to deals on Illinois to Heathrow flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from Illinois to Heathrow?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to Heathrow.

  • Can I find deals for business class flights from Illinois to Heathrow?

    Yes. Cheapflights offers flight deals from Illinois to Heathrow by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Illinois to London Heathrow Airport?

    Currently, January is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £480). Flying from Illinois to London Heathrow Airport in June is currently the most expensive (average of £1,023). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near London Heathrow Airport?

Book flights to London Heathrow Airport if you plan to visit one of these locations
Hounslow
Milton Keynes
Luton
Gatwick
Wembley
Ilford
Slough
Hayes
Croydon
Colchester
Brentford
Eastbourne
Northampton
Watford
Southend-on-Sea
Swindon
Enfield
Kingston upon Thames
Southall
Poole

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Alternative routes for Illinois to Heathrow

See prices for flight routes from nearby airports that may be better suited for you.
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Top 7 airlines flying from Illinois to Heathrow

Discover the top 7 airlines that operate flights from Illinois to Heathrow. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 17 August 2026.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapest£361Average£558FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
American AirlinesCheapest£382Average£817FlexibilityNo cancel feeOn-time71%
Search American Airlines flights
British AirwaysCheapest£419Average£620FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Aer LingusCheapest£456Average£800FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
United AirlinesCheapest£504Average£804FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
IberiaCheapest£514Average£691FlexibilityNo cancel feeOn-time77%
Search Iberia flights
JetBlueCheapest£735Average£875FlexibilityNo cancel feeOn-time62%
Search JetBlue flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Illinois to Heathrow?

When you search for this flight from Illinois to Heathrow, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Illinois to Heathrow?

By finding flights from multiple airlines and providers at completely no cost, Cheapflights helps millions of users like you annually find the best flights to Heathrow from Illinois.

Can Cheapflights find flights from Illinois to Heathrow with no change fees?

Cheapflights does show flights with no change fees to all users. To see these options for flights from Illinois to Heathrow, users can toggle the no change fees filter when performing a flight search.

Can Cheapflights notify me if prices for flights from Illinois to Heathrow become cheaper?

Yes, Cheapflights offers price alerts on Illinois to Heathrow flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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