Cheap Flights from Decatur (DEC) to St. Louis (CPS)

Popular airlines from Decatur, IL (DEC) to St. Louis, MO (CPS-St. Louis Downtown)

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Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $316
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $316
Flights from Decatur (DEC) to St. Louis (CPS)
Origin airport
Decatur
Destination airport
St. Louis Downtown
Distance
110 mi

Decatur to St. Louis Flights

The cheapest times to fly from Decatur to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Decatur to St. Louis are during the month of . You can find some of the cheapest flights from Decatur to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Decatur to St. Louis

Sunday is one of the best days to book for cheap flights from Decatur to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Decatur to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Decatur to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Decatur to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Decatur to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS) cost?
Snag a cheap one-way flight or cheap return flight from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight deals on this route.
What is the cheapest month to fly from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS)?
Planning your getaway for is a good way to save, as it's the cheapest month for flights between DEC and CPS. You'll usually find the lowest fares during the off-season.
What is the cheapest airline that flies from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS)?
Expedia's filter tool lets you easily compare airlines, flight times and baggage options all in one place. Customize the search to your preferences, then sort by "Price (lowest to highest)" to see which carrier offers the cheapest DEC to CPS flight.
How many flights per day from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS)?
Nonstop flights from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS) aren't available daily, so you'll need to take a flight with a layover. Explore your options with Expedia's filters. Enter your dates and choose either "1 Stop" or "2+ Stops."
What day of the week has the most flights from DEC to CPS?
Friday is generally the busiest day for flights, while Tuesday is often the quietest.* Keep in mind that flight schedules can vary based on various factors, including the airline and season.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS)?
To avoid potential delays on the Decatur Airport (DEC) to St. Louis Downtown Airport (CPS) route, aim to fly before 3 PM. Flights after this time are 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS) last-minute?
Holding off until just before your departure to book your flight from DEC to CPS often results in higher prices. While it's possible to find some last-minute discounts, they aren't always guaranteed. Keep your travel plans flexible to maximize your chances of getting a bargain.
Is it cheaper to book a DEC to CPS flight and hotel package?
Compared with arranging hotels and flights separately, booking a DEC to CPS flight and hotel package with Expedia could lead to significant savings. What's more, having everything in one place will take the hassle out of planning your trip. Simply pick your flights and choose from our wide range of stays, then customize your trip with extras like activities, tours and car rentals.
Can I cancel or change the date of my flight from Decatur Airport (DEC) to St. Louis Downtown Airport (CPS)?
Generally, it's possible to cancel or reschedule your DEC to CPS flight. However, for bookings made more than 24 hours ago, additional fees may apply. Check your airline's policies in your itinerary to see what changes are possible and if any costs are involved. You'll also find more information on our Customer Service portal.

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