Cheap flights from London Heathrow Airport to Chicago from €423

The cheapest month to fly to Chicago from London Heathrow Airport is in September. Flight prices, which tend to average around €512, are often lower during this time because this is during the off-season. If you don’t want to visit Chicago in September, then you should wait until February to fly from London Heathrow Airport, when ticket prices are also cheap, with an average price of €531.

On average, the least expensive day to fly to Chicago from London Heathrow Airport is on a Friday. momondo users have found tickets for Friday departures for as low as €1,029. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Tuesday as prices are generally higher than usual. According to our data, the average ticket price to Chicago on Tuesday is €3,235.

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 €642 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 €537 on momondo.

There is only 1 cabin class available to choose from on London Heathrow to Chicago flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Historically, on average around 10% 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 169 minutes.

Generally, flights departing at night tend to experience fewer delays. Flights departing in the evening have, in the past, seen delays more frequently in comparison.

Thursday is statistically the day of the week that experiences the fewest delays on this flight route. Friday 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 5% of their flights experiencing any sort of delay.

As of March 2026, there are 38 flights per day flying from London Heathrow Airport to Chicago. The most common time of day flights depart is 12:00, with 64% of flights taking off in the afternoon.

As of March 2026, there are 268 flights per week flying from London Heathrow Airport to Chicago. The most common day of the week flights depart is Mon, with 16% of flights taking off on this day.