Cheap flights from London Heathrow Airport to Chicago from £378

The cheapest month to fly to Chicago from London Heathrow Airport is in February. Flight prices, which tend to average around £457, are often lower during this time because this is during the off-season. If you aren’t able to travel during the month of February, then book flights to Chicago from London Heathrow Airport during September instead. Flights to Chicago in September, while not as cheap as those in February, still average around £507.

The cheapest day to depart on your flight to Chicago is on a Thursday when prices can be found for as low as £671. This is often the case because there is less demand to fly during this day of the week. The most expensive day to fly to Chicago is Sunday, with ticket prices averaging around £692.

Flying to Chicago from London Heathrow Airport at midday is the least expensive time of day to depart. momondo users have found prices as low as £658 when looking at flights departing at midday. Flights in the morning are often more expensive, with an average ticket price of £690.

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

You are more likely to see cheaper flights to Chicago from London Heathrow Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to Chicago for around £618 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Chicago from London Heathrow Airport for as low as £575 on momondo.

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

No. A direct flight is the cheapest option for a flight between London Heathrow Airport to Chicago.

As of August 2026, prices for London Heathrow Airport to Chicago flights are approximately 18% cheaper when compared to flights at the same time last year.

United Airlines, SWISS, and JetBlue are the most popular carriers operating from London Heathrow to Chicago

British Airways, Lufthansa and Icelandair are the top three most popular airlines that fly to Chicago from London Heathrow Airport according to our data. British Airways is the first choice among our users, with 61% of people opting to fly with this airline when travelling to Chicago. Keep in mind that there are 14 different airlines that fly to Chicago on a routine basis, so you have a few additional options to choose from.

Historically, on average around 11% of flights between London and Chicago have experienced a delay on any given week. The average delay length over the past 12 months has been 182 minutes.

Generally, flights departing in the morning tend to experience fewer delays. Flights departing in the early afternoon have, in the past, seen delays more frequently in comparison.

Wednesday is statistically the day of the week that experiences the fewest delays on this flight route. Tuesday has historically seen more delays on average compared to the rest of the week.

According to our data, United Airlines have had the fewest delays on this route over the last 12 months, with about 6% of their flights experiencing any sort of delay.

Reykjavik (KEF) was the most common stop: 44% of momondo users choosing one-stop flights on this route connected there.

Flights via Copenhagen (CPH) offer the lowest average return price of £456.

Flights connecting via Detroit (DTW) have the shortest average one-way travel time: 11h 34m.

Zurich (ZRH) has the shortest average stopover time for this route: 1h 13m.

The number of flights available between London Heathrow Airport and Chicago is 49 per day as of August 2026. The most frequent departure time is 11:00, with 50% of daily flights leaving at midday.

The number of flights available between London Heathrow Airport and Chicago is 346 per week as of August 2026. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.