Daily cleaning, installation of cabin HEPA filters on flights from Illinois to Medan
|March||Best time to beat the crowds with an average 4% drop in price.|
|January||Most popular time to fly with an average 11% increase in price.|
Average price round-trip
|$1,154||(avg. price over the last 2 weeks)|
Good deal round-trip
Good deal one-way
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 Illinois to Medan.
KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Medan from Illinois is likely to change within 7 days, so travelers know whether to wait or book now.
Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Medan with an airline and back to Illinois with another airline.
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 to Medan from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.
Scores according to KAYAK customer reviews
Cons: "Poor customer service and lack of care for loyal passengers"
Pros: "One of several preferred airlines when flying to Asia. Really enjoy their service, and it's wonderful to wake up to many beauties in view!"
Pros: "Great inflight entertainment"
Cons: "Have WiFi that is working"
Pros: "Very cramped seats"
Cons: "flight on time. flight was delayed and gate changed"
Pros: "Movies selection is great. Seating space is comfortable."
Cons: "Boarding process could’ve been smoother"
Pros: "Great foods and services"
Cons: "The plane needs upgrade business class seats"
Cons: "Flat bed in business class was disappointing. No way anyone taller than 6’ could stretch out. Overall, it was an inferior experience to business class on Cathay Pacific, which sets the standard IMO."
Pros: "Efficiency, good."
Pros: "Handset to control screen didn’t work. Airline reimbursed me with $75 voucher for inflight duty-free shop."
Pros: "Better flight as bigger craft and no neighbours in my row so I got some sleep."
Pros: "Food was good"
Cons: "Boarding was just ok, but departure delayed by half hour. Seats were really poor. Zero comfort.. felt like sitting on a cramped park bench. Entertainment system is ancient. Can't see and can't listen properly. Didn't expect this type of horrible aircraft from Singapore Airlines!"
Cons: "Short and sweet. Flight left on time and landed about 15 mins early. Crew was wonderful"
Pros: "smooth boarding process excellent enterntainment offered food is also quite good"
Cons: "seats seem to get smaller, less comfortable then I am used to with Singapore Airlines"
Pros: "The inflight entertainment was great, lots of movie selections"
Cons: "The leg room was horrible. Honestly the worst space I've ever had in a flight. I was shocked considering Singapore air is considered one of the best airlines"
Pros: "My neighbor"
Cons: "Fight war delayed and we got a security check upon arrival"
Pros: "Everything From the food to the drinks to the comfort"
Pros: "The flight attendants were nice, attentive and joyful!"
Cons: "Sitting in a middle seat. Was told at the jetway counter no aisle or window seats were available. I saw no fewer than 5 empty aisle seats in my area."
Pros: "crew very helpful with seating service on board also good"
Cons: "head phones for entertainment very uncomfortable Food not to my taste"
Pros: "Boarding was good and the flight time was shorter than expected."
Cons: "My son did not like any of the meal selections between beef and fish. We asked for a ramen noodle cup instead that the flight crew denied they had, only after seeing them offer it to another family just seconds before. I was very disappointed!! I believe the flight attendant knew of my concerns because she started asking me if the service was ok. If your doing a good job, then you won’t have to ask."
Pros: "Excellent service"
Cons: "Very poor on board entertainment"
Pros: "Great amount of legroom in the seats we were lucky enough to be granted. Entertainment was good!"
Cons: "Frantic service from crew. They seemed anxious and rushed at all times. Food was also very average."
Pros: "Services, the Care and the Concern!"
Pros: "great crew service. my first time flying with singapore airlines. they delivered!"
Cons: "Boarding at Singapore airport was shocking, as we had to wait 6 hours for our flight. Rating low to the crew mainly because of the ground staff as they were not very communicative to begin with about the explanation for our delay. Only when the passengers got a bit more vocal about wanting explanations, they started giving us a bit more information. All estimated times given for boarding the flight were incorrect by a big margin! Seemed more like they were giving shorter wait time for boarding just to please the passengers, where as they were well aware of how long the wait would be."
Pros: "I liked there was an opportunity to bid on an upgrade"
Cons: "Our bid was rejected yet there were empty seats in premium economy. Our bid was within the recommended range. You certainly would not have lost money upgrading us."
Pros: "Entertainment even in economy class was excellent -- tons of movies, games, etc. Cabin crew were friendly. Bathroom was very large."
Cons: "In economy, seating was incredibly tight (very little legroom) and at least in my seat, very little reclining. For a 14 hour flight through the night, it made it very difficult to actually get any rest. Food was OK."
Cons: "The crew was rude when asking me to window shed."
Pros: "The service, seats, food, drinks and bed!"
Pros: "Crew was nice"
Cons: "Aircond isn’t working at seat 60 onwards. Warm. Sweaty."
Pros: "Comfy chairs and good food on Singapore Airlines."
Cons: "Some of the male crew didn't do anything, the females did all the interactive work in serving and helping the disabled as far as I could see."
Pros: "the crews were very polite and very helpful"
Pros: "The friendliness of the staff, the food and overall the experience."
Cons: "That our bags weren't check in all the way to SEA"
Pros: "Nothing specific"
Cons: "No real dramas"
Pros: "Great service with a smile and can do attitude"
Pros: "Singapore service is always outstanding"
Cons: "temp on plane was freezing and even two blankets did not suffice. Everyone was really cold."
Pros: "Attendants are always nice, flight is always smooth."
Pros: "Crew and boarding were efficient"
Cons: "Choice to have meal immediately after takeoff or just before landing. I chose to have it just after take-off but didn't expect not to have any breakfast. Not fun leaving the plane hungry."
Cons: "Extremely cramped flight in regular Economy."
Pros: "Service is amazing! I loved that airplane had Christmas decorations on the walls and great choices of food and beverages."
Pros: "I am still trying to find my bags. I missed my connection and Jet Blue made me stand in a line to get rebooked for 7 hours. Unprofessional, uncaring. None of this was my fault but everyone who represents Jet Blue treated me as if it were. Never again"
Cons: "Breakfast was pathetic. Not fresh. For 16 hours flight only two meals were served and no snacks were provided"
Pros: "Great food, friendly staff, on time... what else do you need?"
Pros: "What did I like??? Um, EVERYTHING! First off I got a great price under $850 round trip to NRT from LAX was a steal! They let you check two large suit cases plus a carry on and a personal item. That all FREE!!! I travel pretty light but it was great to know they don't Nickle and dime you for bags or anything else for that matter. Staff looks amazing and treats you first class even when your in economy. They are so polite and really genuinely want to give you a above and beyond experience. And they over achieve at it! They meals are great and very satisfying. The planes are big and roomy even in economy seats. On our return flight we had a brand new plane which had a sleek touch screen monitor and controller. There mad tons of media available (articles, language games, games, movies, tv shows and more) with USB ports to charge devices on each seat. Plus 10inch personal monitors. Earbuds were included free of charge, aswell as socks toothbrush and tooth paste. They have is two big meals on our direct flight (awesome that they have direct flights). Plus, they offered free snacks too and gave us a full can of soda vs. a small cup. They come through several times offering coffee, tea, water and snacks. All free of charge. This was my first time flying Singapore Airlines and I loved it!!! I wish Everyone was this amazing! Norwegian Airlines was the opposite as far as charging for everything! Had to pay each stop for any luggage ($100 per checked bag). No meals free or charge. They wanted money for everything! And yea a skimpy sandwich was $9.00 :(."
Pros: "I like your new entertainment devices and big screen"
Cons: "the number of movies is a little bit less. the category of videos is not clear."
Cons: "Earphones were poor and when replaced still did t work well"
Pros: "Crew was wonderful. Comfortable seat with nice meal. Overall loved it"
Pros: "Having social distance space to take a nap"
Cons: "I sat in the middle seat of the middle of the plane and the staff kept skipping me during meal and drink service because they assumed the other side took care of me. So that was annoying. I had to keep flagging them down."
Pros: "The check-in crew in Chicago was very nice and efficient. The flight crew on-board were not friendly, they were very curt and rushed, and did not go out of their way to be helpful."
Cons: "Friendlier staff during the flight. Better food for breakfast. The connection port for my headphones did not work...I would not have been able to watch movies if I hadn't brought my own single connection head phones."
Pros: "The crew was really nice and very attentive."
Pros: "The aircraft was comfortable and the electronic amenities were decent and needs improvement"
Cons: "Free WiFi and Dancing boys"
Pros: "The flight crew/staff were professional and very helpful and accommodating to the passengers from check in to deboarding."
Cons: "Seats were a little close, especially for a long flight, with meals."
Pros: "The crew was great."
Cons: "Food wasn't that great."
Pros: "The crew was amazing. One of the onboarding staff was exceptional. Some onboarding staffs were unfriendly."
Cons: "Not allowing a laptop bag unlike Etihad, Emirates and other airlines was a bummer."
Pros: "Very courteous, friendly, professional flight crew and gate crew."
Cons: "Nothing to mention...very pleased"
Pros: "I was at airport 1 hour before the flight time But they already closed the gate, and I missed the flight, and my return flight is gone too Omg to much for me"
Cons: "I wish you can do something for me Because the tickets is really expensive"
Cons: "Slow boarding while passengers stand in the queue, late take off"
Cons: "Refund my ticket"
Pros: "This was my first experience with Qatar & it was outstanding. Crew members are extremely courteous & helpful. The aircraft seats in economy class were roomy & comfortable. Bathrooms were kept clean throughout the long flight. Food was very good as was the selection of flight entertainment. Can't thi"
Pros: "seat was great"
Cons: "flight attendant should be nicer"
Pros: "The crew was very friendly and helpful throughout the flight"
Cons: "The boarding process in Chicago wasn’t great. Zones were not used"
Pros: "Delighteful experience"
Cons: "Better guidance at transit stop"
Pros: "Plenty of room to move around"
Pros: "Food was excellent and the crew updated us through out the flight"
Cons: "That fee for overweight was excessive"
Pros: "Q-suits. Very comfortable and private. Great upgrade to the 777. WiFi now available for very reasonable price"
Cons: "Bus transfer to Termial 5 is VERY poorly organized and takes over an hour. This makes it harder to get to Terminal 5 even if you don't have to clear security again. Seats had a bar under the padding at about the position of my hips. Uncomfortable to sleep for several hours"
Cons: "Ord to Doh: People kept window blinds open all through 15 hour flight Flight temperature kept very warm"
Pros: "Good food and good hospitality"
Cons: "The gentleman next to me had broad shoulders, so I spent most of the flight with my body a bit twisted, and eating without being able to move my right arm normally was undesirable. The cabin was kept a bit warm throughout the flight. We had a long wait (30 - 45 minutes after leaving the gate) before takeoff."
Pros: "Video on Demand at each seat in coach. Friendly staff. Also patient staff, what with the languages they have to cover with each flight. The airline goes everywhere so it’s impossible to say what anyone will be speaking."
Pros: "B777 Dreamliner is dreamy. Lots of overhead luggage space. Decent leg room (could always be more). Great individual entertainment screen for long transcontinental flights. Flight staff was a mixed international crew, very friendly, unpretentious, polite and just nice compared to other airlines. The planes they use seem very new. Would definitely recommend Qatar Air over Aeroflot any day."
Cons: "Food was decent for airline food but nothing to rave about and as with most airlines uses too much plastic packaging. Although I was pleased that some of the flights used metal flatware, but still too much waste in the industry in my opinion. Also, the headphone jack was not compatible with my headphones. The type used on the 777 is the dual pronged one. I did not have an adapter so had to use the crappy headphones that are provided."
Pros: "Food was great Seats were comfortable Everyone was super nice"
Pros: "Courteous and friendly staff, on the plane and at the airports. Gave advice and directions when asked. Asked about time for food serving and said anytime you want something, come to the galley."
Cons: "A chorus of crying infants..."
Pros: "Great service and crew"
Cons: "I’m a 6’3” in shape man. I selected the bulkhead seats for extra leg room. Great crew, but my shoulders stuck past the seat edge 3” on both sides. Qatar should revise their claim of most room in cabin - this 12 hour flight was one of the roughest I’ve had in a long time comfort wise."
Pros: "Good food. Great staff and service"
Cons: "I wish there was more seating room and unusually long waiting time for toilets."
Pros: "Checkin crew was rude and was not at all respectful"
Cons: "Checkin crew was rude and was not at all respectful"
Cons: "Boarding at JFK very disorganized. Poor system. No vetting of wheel chair users many fakers."
Pros: "Every thing is great."
Cons: "Food Seat great service"
Pros: "On demand entertainment systems seem standard, as I’ve flown Qatar several times and always had it. Friendly staff. And Doha is a great connection airport."
Pros: "I have made more than 6 round trips on Qatar Airways for AMD-ORD-AMD in last 18 months and can not be happier!!"
Pros: "My flight from Chicago to Doha was late to come in and there was a gate agent waiting for us and two other passengers with a sign when we got off the plane. He told us that our flight had already left but he would get us on the next one. We ended up getting seats on the next flight but then were also given the option to get a temporary visa and explore Doha for the night. We opted for the comped night which included a very nice hotel and $100 in meal vouchers. We absolutely LOVED Doha and the hotel and food was fantastic! I don't think I have ever received better service from an airline or a hotel. We ended up walking around Souq Waquif and the downtown until 1am (we are two young females!) with no issue and just used Uber to get to and from the hotel. Everything was so well laid out for us! No complaints whatsoever!"
Pros: "smooth and on time with efficient service."
Pros: "Hospitality, boarding process"
Cons: "Food was slightly undercooked (chicken). Should have better process to check for that"
Pros: "Enjoyed the food and the service from the crew. Plane was new and relatively new and comfortable."
Cons: "The check in agents were not very polite or helpful. They did not offer much assistance and help for a first time customer on Qatar Airways. My bags were also not loaded onto the plane and had to arrive on a later flight"
Pros: "Seats are comfortable with plenty of leg space. Aircrafts were clean and tidy. Landing and take off were smoothest I have ever experienced."
Cons: "Menu choice was very basic and quantity was also poor. Food quality was below par in terms of taste and presentation. In-flight crew was inefficient and flow. Meal trays laid on meal tables for hours after the passengers finished food. Flight attendants literally responded in over 30 min of call. I pressed special meals online before boarding. However, the flight attendants were not sure. They went back to kitchen to verify that and return with the ordered meal."
Cons: "Luggage items are missing."
Pros: "It was excellent."
Cons: "It was excellent."
Cons: "No consistency with hand luggage. My companions and I were held to strict weight limits. Others were getting on with three and four bags."
Pros: "The entertainment options were fantastic! The flight attendants were very cordial and hardworking."
Cons: "I was very pleased with my flight. I really have I complaints."
Pros: "everything was as expected from a world-class in the travel world."
Cons: "In economy class, the seats are not as roomy as I thought and leg room space is not suited for overseas 12+ hours travel comfort."
Pros: "Vegetarian food options"
Pros: "The Chicago flight was more than hour late so had to miss my cincinnati connection. Had to wait for 4 hours at the airport to catch my next flight- making the long journey even longer. No priority lounge access provided to make up for the delay. Qatar never getting my business again."
Pros: "Inflight services, food"
Cons: "Wheelchair services in India, person left in between and had to walk with pain in my foot for a distance."
Cons: "Boarding staff give us wrong advice to make extra money from the passenger. They also pressurized us to decide quickly. our each check in baggage was over weight 1 KG or less than 1 KG due to faulty scale at home. Instead of giving us a choice or advice that you are allowed two more hand bags. They pressurized us to make one baggage over weight from all 7 bags and harassed us to do it quickly because they are closing counter in 20 minutes. That's how they charged me another $65. Also they lied on the counter that your seats are in a row but when i went into the plane our seats were separate. Lesson learned don't trust the person over the counter of Qatar airways."
Cons: "I fell sick and my doctor advised against flying. Tried calling Swiss Air and JustFly.com: 6 calls back and forth and 7 hours on hold, no help. Finally got advised on driving to the airport to make the flight change at the Swiss Air counter at O’Hare. The representative told me to bring a note from doctor to switch flights. I did the next day. The same representative looked me in the eye after advising the day before and said there’s nothing she could do. Why make an elderly sick person drive to the airport again if you know already you cannot help??Absolutely terrible experience, no help from the airline or travel agency. Total loss of the full price of the ticket."
Pros: "Great smooth flight, crew were friendly and many movies and shoes to choose from."
Cons: "Seats are tight and not much leg room for the unfortunate ones who fly Economy class. Food was ok."
Pros: "Service was excellent"
Cons: "Carry on baggage size misleading"
Cons: "Crew was rude to passengers. One passenger asked for extra bread and crew arrogantly commented , we dont give but ok take one."
Pros: "Everything was just dandy!"
Pros: "Amazing food, There were pillows, blankets and earbuds on every seat. Really a great flight overall and I would fly with them again."
Cons: "The only minor complaint was that the seats are so small that when the person in front of you reclines, you literally can’t get out of your seat."
Pros: "Best food I've ever had on an airline! Great flight. Not too full."
Cons: "Arm rests didn't lift all the way up on the plane."
Pros: "Crew was attentive to passenger needs in a quiet way: without fanfare, did all possible to make it a pleasant, comfortable trip. In fact, went out of their way to get me a wheelchair ride to next flight, which I dearly needed"
Cons: "First flight was delayed due to circumstances outside of airline’s control. They managed to get us there and help me with wheelchair, etc to make flight. Great service and kindness"
Pros: "Seats were comfortable and the crew was great"
Cons: "I had a carry-on sized bag which would have fit in the overhead compartment. I was told that it would not fit the Swiss Air compartment, thus was forced to check it at the gate. I expressed my concern that it would get lost (thus the reason I never opt to check bags) and was assured "They are very efficient in Zurich." When we arrived in Madrid, my bag was not at the carousel. I was told at Customer Service that it was on another flight, but that they could deliver it to my Airbnb between 4-7 pm. I had to wait there instead of enjoying my vacation to wait for my bag. The bag did not arrive until 10:30 pm. I did not have my clothes or belongings with me all day. Swiss Air in particular needs to update their overhead compartment regulations, as my bag definitely would have fit there, and could have avoided this entire situations."
Cons: "My special meal wasn’t available."
Cons: "The seats in coach plus and Bussines were terrible"
Pros: "Excellent Service. Excellent food."
Pros: "Most everything about the process."
Cons: "Person in front reclined chair fully and left virtually no room for sitting!"
Pros: "Not very much. At least the staff was friendly."
Cons: "It seems like they always sit me next to the bathrooms. If I'm paying that much for a flight, I don't really appreciate having hordes of people lined up for the bathroom, bumping me constantly. I also don't very much like the door constantly opening and closing, due to noise and the obvious smell. Furthermore, I sat next to a family with 2 screaming babies. Overall, 8 hours of agony. Not a good experience at all."
Pros: "The flight attendants seemed very courteous, but unable to do anything about the situation."
Cons: "We had a family of four sitting behind us. The father yelled all the time. They took up four overhead bins and he was frequently up and down getting things out of the bins. His very hairy large belly was touching my daughters head every time. He and his children punched the backs of our seats on a regular basis. My back was in constant pain and I was unable to do very many things due to the back pain during my "vacation", The flight attendants had to remind the parents that their children could not stand on the seats during takeoff or crawl around under the seats. No ability to change seats or I would have. I didn't have a problem with the other children on the flight, when they were crying their parents tried to do something. However these people brought playdough for their child to roll out or punch on the seat tray and all they did was constantly yell loudly at their children, Well not about the kicking, punching, or crawling around. Just yell in general at them."
Pros: "On time and friendly service"
Cons: "Poor selection of films, cramped seats and mediocre dinner"
Pros: "Airline services and great time scheduling"
Cons: "Upon arriving to Chicago airport the Chicago airport couldn't get passengers off the plane due to mechanical issue"
Cons: "Warm breakfast in coach would be appreciated, but i understand it is just coach."
Pros: "I like the space in business class and the staff were really nice"
Cons: "The seats were not comfortable, they ran out of scotch (single malt) and I only had 1 drink"
Pros: "Food, staff, service"
Cons: "No leg room"
Pros: "Friendly crew, decent meal, and above-average entertainment systems"
Cons: "Confusing boarding process, outdated and worn seats and technology, unable to select seats when booked as a United codeshare."
Cons: "Seat in front of you tilts back and gives you NO room. Horrible!!"
Cons: "Airline lost my flight, no explanation and or apology. Seats were terrible could not move when seat in front was reclined. No economy plus, no reciprocal consideration for gold status on star alliance except for one checked bag free. I will never fly Swiss again"
Cons: "There was a supposed difficulty with my entry in Europe when I tried to Check into Chicago. I thought that I had to cancel my flight. Swiss air representatives had to do much consultation, which took nearly an hour, while I was standing there the whole time. At the end, I was thanked for my patience and told all should be well and not even given a small upgrade for the distress this caused me. Traveling is disagreeable in general now, and personally, even moreso after this episode."
Pros: "On time, efficient, good service, professional"
Cons: "They lost my bag and after 24 hours, still no word on whether it's been located."
Pros: "Very prompt and courteus"
Cons: "Baggage missing for three days. Communication poor."
Pros: "Crew was great! Boarded quickly! Alot of movies to watch!"
Cons: "When getting our meals the flight attendants didn't ask anyone to move their seats back up so it was difficult to eat since there was no space."
Pros: "Polite crew"
Cons: "The service and food was excellent. There is no question about dislike"
Pros: "Very friendly staff, a wide variety of entertainment options."
Cons: "I'm a pretty small person (5'4 and 110 pounds) and it was very hard for me to get comfortable. Not that you'd expect much out of an economy class seat."
Cons: "Not. Lot of room for legs. Slection of movies very poor. Very old movies mostly"
Pros: "Flight attendants were perfect, sincere, and friendly. Great selection of free movies."
Cons: "I could not open my laptop and do any work once the person in front of me put their seat back. Big time bummer."
Pros: "Crew and flight service are excellent top notch. Also they are very friendly and helpful. Make flight enjoyable."
Cons: "Seats are too close together in coach, very cramped and uncomfortable if you are a tall or large person."
Pros: "Good entertainment"
Cons: "Couldn't control the airflow at your seat."
Cons: "My flight attendant was rude and condescending the entire flight. I don't appreciated being treated like a moron for asking someone to repeat a question."
Pros: "The flight crew were friendly and helpful. The food served on our flight to Zurich was delicious. We loved the big movie selection which helped pass the time."
Cons: "The leg room was terrible on this plane. If anyone reclined their seats, you were trapped and could barely get out of the row to get up or go to the bathroom. Boarding was a bit like herding cats and everyone was jammed up trying to get on without any orderly direction."
Pros: "Staff were courteous and there was abundant food and beverage service."
Cons: "No child activities were distributed by the crew (like they did for our return flight)."
Cons: "seat size and comfort. Had metal nox take good part of my footroom. small aisle. Food lousy."
Pros: "First time flying with swiss air, loved everything about this airline!!"
Cons: "Professionalism, outstanding service, no problems, no stress, no issues, flawless!!!!!"
Pros: "Our attendant was very nice with a great attitude."
Cons: "Luggage line in Zurich at airplane"
Pros: "Very good. Good entertainment options."
Pros: "More space with a window seat than I am used to. Shoulder didn't even touch the side of the plan. Loaded the back of the plan first after premium and those needing extra time."
Cons: "By the time they got to me I only had one choice for the dinner meal. No restroom in the back of the plane so I got stuck waiting for the cart to come all the way down the aisle before I could go to use it."
Pros: "Flight boarding was quick and fast and food was great."
Cons: "Seats had no room and if someone in front reclined the tv was right in your face. Also what happen to having individual fans above. It was so hot I felt sick the whole way and when we pushed the call button no one came had to flag down an flight attendant walking by. We had to ask three more times to get the heat down. Overall it was okay."
Pros: "Everything else."
Cons: "The selection of movies was not impressive"
Pros: "I like"
Cons: "I like Swiss airline"
Cons: "Arm rest doesn't go up all the way. Very difficult to get out when seats are reclined in front of you"
Airlines flying from Illinois to Medan have enacted additional safety measures and adjusted policies to better accommodate travelers. Policies vary by airline.
Daily cleaning, installation of cabin HEPA filters on flights from Illinois to Medan
Masks required on board, masks provided on flights from Illinois to Medan
Social distancing seating
Middle seats unavailable to book on flights from Illinois to Medan
Testing for antibodies, testing for symptoms for flights from Illinois to Medan
Waiving of change fees. Search flexible flights from Illinois to Medan