Cheap flights from Illinois to London from $306

The month of January is, on average, the cheapest month to fly to London Heathrow Airport from Illinois, with most prices found around $650. If you’re not able to fly to London Heathrow Airport in January, then February is your next best option. Flight prices from Illinois to London Heathrow Airport during February average around $710.

Our data shows that Tuesday is the least expensive day to fly to London Heathrow Airport. Tickets to fly out on this day can be as low as $862. The most expensive day to fly to London Heathrow Airport is Saturday, with ticket prices averaging around $1,073.

According to our data, the cheapest time of day to fly to London Heathrow Airport is in the afternoon. momondo users have found flights departing from Illinois to London Heathrow Airport in the afternoon for as low as $955. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights in the evening are often more expensive with an average ticket price of $972.

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

You are more likely to see cheaper flights to London Heathrow Airport from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around $869 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Illinois for as low as $807 on momondo.

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

United Airlines, Delta, and British Airways are the most popular carriers operating from Illinois to London Heathrow

British Airways, American Airlines and United Airlines are the top three most popular airlines that fly to London Heathrow Airport from Illinois according to our data. British Airways is the first choice among our users, with 42% of people opting to fly with this airline when traveling to London Heathrow Airport. Keep in mind that there are 15 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.

As of August 2026, there are 49 flights per day flying from Illinois to London Heathrow Airport. The most common time of day flights depart is 6:00PM, with 76% of flights taking off in the evening.

343 flights are operational weekly from Illinois to London Heathrow Airport as of August 2026. The most popular departure day for this route is Fri, with 17% of flights per week taking off on this day.