Lufthansa's Economy Flex offers preferred seating and same-day flight changes.
Lufthansa's Free Neighbor Seat allows extra space for a fee on long-haul flights.

Most accurate provider | Mytrip 3 stars  | 
|---|---|
Most trusted provider | Mytrip 3 stars  | 
Round-trip from | $97 (American Airlines)  | 
One-way from | $49 (United Airlines)  | 
Popular in | July | 
Cheapest in | September | 
Average price | $259 | 
Good round-trip deal | $472 or less | 
Good one-way deal | $217 or less | 
Fly from
Fly to
Route
Depart
Return
Price
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Sat 1/17
9:59 am-4:45 pm
1 stop6h 46m
Chicago O'Hare Intl
Sun 1/18
5:33 am-11:05 am
1 stop5h 32m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Mon 11/24
12:49 pm-4:52 pm
1 stop4h 03m
Chicago O'Hare Intl
Thu 11/27
5:23 am-9:59 am
1 stop4h 36m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Fri 12/5
10:42 am-11:54 am
1 stop25h 12m
Chicago O'Hare Intl
Sun 12/7
2:36 pm-8:59 am
1 stop18h 23m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Thu 12/18
11:40 am-6:43 pm
1 stop7h 03m
Chicago O'Hare Intl
Thu 12/25
5:31 pm-11:38 pm
1 stop6h 07m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 1/21
6:00 am-1:39 pm
1 stop7h 39m
Chicago O'Hare Intl
Sat 1/31
6:46 pm-11:25 pm
1 stop4h 39m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Thu 12/18
11:40 am-6:43 pm
1 stop7h 03m
Chicago O'Hare Intl
Tue 1/6
6:46 pm-11:25 pm
1 stop4h 39m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 12/17
2:02 pm-6:43 pm
1 stop4h 41m
Chicago O'Hare Intl
Sat 1/10
11:05 am-4:38 pm
1 stop5h 33m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Sat 1/17
6:10 am-1:07 pm
2 stops6h 57m
Chicago O'Hare Intl
Mon 1/19
1:58 pm-11:25 pm
2 stops9h 27m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Sun 1/18
8:05 am-9:40 am
Nonstop1h 35m
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 12/24
8:05 am-9:40 am
Nonstop1h 35m
| Provider | Price Accuracy | Trust Score* | 
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy1 star | Trust Score*3 stars | 
To ensure you get the cheapest price possible for a flight from St. Louis to Chicago O'Hare Intl Airport, you should look to book at least 75 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.
Currently, September is the cheapest month in which you can book a flight from St. Louis to Chicago O'Hare Intl Airport (average of $93). Flying from St. Louis to Chicago O'Hare Intl Airport in August is currently the most expensive (average of $159). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
It’s typically best to fly out from St. Louis to Chicago O'Hare Intl Airport in the morning. Doing so could potentially save you 47% on the flight price compared to flying at noon, which is usually more expensive.
Travelers seeking maximum savings on their St. Louis to Chicago O'Hare Intl Airport flight should consider departing on Thursday mornings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Comfort
Food
Entertainment
Crew
Overall
Boarding
Reviews
Anonymous,Oct 2025
YUL - ORD
Comfort
Food
Entertainment
Crew
Overall
Boarding
Reviews
Anonymous,Oct 2025
YUL - ORD
Comfort
Food
Entertainment
Crew
Overall
Boarding
Reviews
Anonymous,Oct 2025
YUL - ORD
Comfort
Food
Entertainment
Crew
Overall
Boarding
Reviews
Anonymous,Oct 2025
YUL - ORD
| Airline | Cheapest | Average | Flexibility | On-time | 
|---|---|---|---|---|
| Cheapest$113 | Average$278 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$115 | Average$311 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$140 | Average$221 | FlexibilityNo cancel fee | On-timeN/A |