฿13,115 Find Cheap Flights to Illinois – Compare and Save

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KAYAK's insights & trends for flights to Illinois

Get data-powered insights and trends into flights to Illinois to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from Thailand to Illinois?

The cheapest month for flights from Thailand to Illinois is September, when tickets cost ฿20,471 (return) on average. On the other hand, the most expensive months are January and March, when the average cost of round-trip tickets is ฿32,954 and ฿28,160 respectively.

How far in advance should I book a flight from Thailand to Illinois?

To get a below-average price on a flight from Thailand to Illinois, you should book around 8 weeks before departure, which saves you about 49% compared to booking last-minute. For the absolute cheapest price, our data suggests you should book 18 weeks before departure.

Good to know

Low season

February

Cheapest flight

฿13,115
Best time to beat the crowds (12% less expensive on average)
Most popular time to fly (46% more expensive on average)
Flight from Chiang Mai to Chicago O'Hare Airport

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Thailand to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Thailand to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Thailand to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Thailand to Illinois is likely to change within 7 days, so travellers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Thailand to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional return ticket. You could then fly from Thailand to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Thailand to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Thailand to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top tips for finding cheap flights to Illinois

  • Enter your preferred departure airport and travel dates into the search form above to unlock the latest Illinois flight deals.

Reviews of the top 5 airlines flying to Illinois

 
Need help choosing which airline to fly with from Thailand to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.4
Korean AirOverall score based on 1220 reviews
8.7Crew
8.1Food
8.3Comfort
8.5Boarding
8.2Entertainment
Airline reviews

The business class is excellent. I loved the food, and the crew was very attentive and professional. From boarding to arrival, everything felt smooth and well-organised.

10.0 ExcellentFiruz, Apr 2026
Read more Korean Air reviews

The business class is excellent. I loved the food, and the crew was very attentive and professional. From boarding to arrival, everything felt smooth and well-organised.

AAAAHHHH... It was shocking in a very positive way, the attention to detail, the courtesy, the manners of all personnel on board, the constant honest smiling. You can see and feel they take pride in all they do no matter how trivial. The plane in general was very comfortable. I can't wait to do it again

Great service and comfort level. You can have more of vegetarian food options.

It’s great, long flight and arrive safe at destination

Everything was excellent as I expected. They also had a very caring crew. I had a headache and asked a Tylenol. The crew members kept checking with me how I was doing.

They were trying to get people to check luggage because the over head compartments were full but when we boarded there were lots of empty places that people could have put the luggage.

I can't believe they put my wife and I in the two middle seats! It is a very long flight and we had single flyers on either side of us blocking the way to the bathroom! There's no reason to not give one of us the isle seat so we could have managed bathroom needs and snacks with convenience. So I think very poorly of Korean air to put us both in the middle, I've never had that happen before and will probably avoid this airline in the future because of this. We tried to have them change it but they didn't so you pretty much lost a customer because of it.

One of the flight attendants stepped on my foot. I was on the aisle seat. A lady inside needed to get out. So Instood. Just then, a flight attentendant came wuicklybtheoughbthe aisle and stepprd on my sock covered toes. I let out a small sound. She stopped momentarily, but didn’t ask how I was just took off of the aisle. Never came back to see how I was. Fortunately, I was not really hurt other than a slight soreness in my toes. But I found that to be very negligent.

Korean Air is unlike any other major airline I have flown with. The grace and respect that the staff has from check in to de-boarding is unmatched. The flight attendants this time were especially wonderful to my five little children. They helped us rearrange to more suitable seating, brought our children’s meals, and patiently waited for them in the aisles when they had to use the bathroom. We felt so welcome and comfortable. I really appreciate the meal voucher when our flight was delayed. I am grateful to have had such an stress-free experience.

Not very comfortable seated in the back plane due to turbulence

"The Room" is the only way to fly. The service was excellent and the stewardesses we all gorgeous and friendly. The boarding process was delayed and the attendants at the airport were not the best.

The flights with ANA were great. The flights with United, not so much.

Attendants were very kind and frequently offered water and snacks. Food was excellent. For some reason, my IFE system would not play dialogue for any media despite my efforts to change to different language voiceovers, restart the system, etc. so I could not watch any videos.

Staff at gate and crew on plane efficient and friendly.

As always, there is that one or two flight attendants that could be better.

It was good. The crew was efficient, food was good

Vegetarian options were not that great. However, the crew and service was awesome

Entertainment was good , comfort on airplane easy hoarding food and drinks was good and a friendly and good service of flight staff

I was good seat to keep stretch my legs . but couldn’t keep my bag in my hand . because they told me can’t keep my seat is no holder , because no seat fronts of us. wish I can put my leg on something higher. but instead of that everything goood.

Good airlines btu ORL airport messed up the return flight for me. Checking out a connecting flight pax is unacceptable.

Excellent service in business class. Well worth the slightly higher fare as it includes lounge access, additional luggage weight and a full hot meal on board.

HAVING ANNOUNCEMENTS FOR PEOPLE TO BOARD ACCORDING TO GROUP IS ESSENTIAL N ENSURING N CUTTING OF QUEUES, EXCEPT FOR PRIORITY CLASS PASSENGERS ON A SEPARATE Q

We still get drinks and a snack. Love the gift bags too.

business class is old but still done very well by the team.

Good experience although the boarding gate is at the terminal extension hence need to leave lounge to head over earlier.

Thai Royal First is very good. Easy check in , Private room in the first class lounge and escort from ticketing to the plane. Once on board crew was very polite, food was outstanding, and the ride was smooth as silk. Restrooms were especially clean. Great Experience

Need to improve on punctuality. My flight was delayed by 1 hour.

Seats were uncomfortable and the vegetarian meal was awful. Some of the entertainment didn't work.

The flight was mostly fine, but I really wished that seats had an outlet to charge devices considering the length of the flight (15 hours there and 14 hours back).

I give EVA 5 stars in every category. I enjoy this airline and it's great team of employees. I always highly recommend EVA to friends and family and everyone.

Sat in the tarmac at O’Hare for 65 minutes. This is a regular occurrence for delta at O’Hare

Delta was fine though my flight was delayed 4 hours into LGA and my return into ORD involved a taxi of 1+ hour to the gate

It was as good as it could be. Flying is not a pleasant experience these days.

The plane was very warm the entire time, despite my vents being open. Additionally, we didn't have internet on our personal devices

There was an unruly family behind us that made the short flight miserable!!! The cabin crew did nothing to contain it.

Flight delay was frustrating, also you cannot checkin online without delta app, web browser check-in throw errors

Got on the plane and sat there for an hour before departure.

Very large passenger too space from my own seat. Arm board couldn’t be lowered because of his size. It wads very uncomfortable trip, as the flight was full couldn’t move anywhere having back pain because of the position in which I was the entire flight.

Cramped seating for me. Luckily it wasn’t a long flight

5 hour delay. They blamed the weather but it was the computer issues they had been dealing with for days.

In between two meals period they're not providing something like banana / cup noodles or bugger. It's really fell sad that I was asking have to wait for 3 hours for second meal. (breakfast)

The crew are timely, friendly and professional. I was very impressed.

They overbooked the flight and reassigned my seat. To add insult they lied that my assigned seat was broken and promptly gave it to someone else

Jain veg meal I opted was super in taste but there was no sweet/desserts with it. I was a big missing in the meal...Please add some sweets to end the meal with 😊

The meat-and-rice combination was a good idea, but the food could use some improvement. The meat looked a bit mushy and almost like ground meat, which wasn’t very appetizing, and the flavor was just average. Other than that, everything else was great.

It is too long a flight to not have free access to internet. Should not charge. Should be some hours free.

My boarding experience was so bad. While traveling from LA to HYD, the boarding was smooth. But the boarding experience from Hyderabad to LA was utterly poor and unprofessional and caused lot of anxiety and stress. Even though we were at the airport Boarding well in advance to accommodate for Immigration and Security Check, Cathay Pacific Boarding On Ground Crew has done a very unprofessional job. It is one thing to follow rules, but being inconsistent and not being able to communicate this clearly is wrong. I was not aware that my laptops weight in my backpacks is also counted against the cabin baggage. While coming from LA to HYD, the ground boarding crew didnt ask for this. They just checked the Cabin bags weight. But at HYD, not for everyone, but for some people they enforced this. Our Checkin Luggage was carefully weighed at home and was accurately measured to 23 kg, Now they asked to move all the weight in our Backpacks where most of the weight is from Laptops and tablets for each family member, I need to accommodate this ~10kg from 6 laptops in to one of the suit cases and pay extra for excess baggage at the airport boarding place. Without a weighing scale how can I accurately move all the items from cabin baggage to one of the suitcase. D Venkatesh is the guy who enforced this. But I dont have a problem with the rule enforcement, but the way he guided us in solving the problem. I was willing to pay the extra money for the extra weight. He told me that the 32 kg excess baggage is allowed with 150 USD. I understood that 32 kg is extra on top of the 23 kg chickin baggage. SO I pushed all of them to one suit case and then when I took this suitcase, I was sent back saying that he meant the total as 32kg but not the excess should be 32 kg, I had to go out of the line make these changes without a scale thrice like this. They literally harassed me. Noushad his manager was sneering at us. When I said, I am going to complain about this, my wife heard him saying some bad words in Hindi. You get one chance to harass your customer. I will never board Cathay Pacific again.

The go to HK trip will easily giving jetlag, but coming back to Chicago has no jetlag because of the time taking off matter.

Just want to do a little more clean up so does not smell like urine.

Wanted different plane design with an additional bathroom at the back of the plane.

More options for your flight to Illinois

Complete your trip to Illinois with a hotel stay or car hire