Cheap flights from London Heathrow Airport to Illinois from £362

The month of September is, on average, the cheapest month to fly to Illinois from London Heathrow Airport, with most prices found around £445. If you aren’t able to travel to Illinois during the month of September, then flying in February is also cheap. Prices for this month can be found on momondo for an average of £462.

The cheapest day to depart on your flight to Illinois is on a Wednesday when prices can be found for as low as £645. This is often the case because there is less demand to fly during this day of the week. Flights from London Heathrow Airport to Illinois on a Sunday will generally be more expensive and average around £673. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our data shows that the cheapest London Heathrow Airport to Illinois flights are usually those with departure times at midday. Our users have found flights to Illinois at midday for as low as £649. In the afternoon is when there is more demand to fly to Illinois, so prices are often more expensive at around £665 per ticket.

Fly from London Heathrow to Chicago O'Hare Intl for the best London Heathrow - Illinois flight prices

You are more likely to see cheaper flights to Illinois from London Heathrow Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around £559 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from London Heathrow Airport for as low as £467 on momondo.

There are 4 cabin classes available to choose from on London Heathrow to Illinois flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

SWISS, Delta, and Icelandair are the most popular carriers operating from London Heathrow to Illinois

British Airways, Lufthansa and United Airlines are the top three most popular airlines that fly to Illinois from London Heathrow Airport according to our data. British Airways is the first choice among our users, with 65% of people opting to fly with this airline when travelling to Illinois. Keep in mind that there are 14 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

As of April 2026, there are 49 flights per day flying from London Heathrow Airport to Illinois. The most common time of day flights depart is 10:00, with 50% of flights taking off in the afternoon.

As of April 2026, 346 flights take off from London Heathrow Airport and land in Illinois each week. The most common flight departure day for this route is Mon, with 16% of weekly flights taking off on this day.