$109 Cheap United flights St. Louis (STL) to Colorado Springs (COS)

You can discover affordable return United Airlines flights from $227 from STL to COS by sorting your results from "Price (lowest to highest)" on Expedia. Or look for bargains from $109 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Start searching one to three months ahead of your travel date to get cheap fares on United Airlines flights from Lambert-St. Louis Intl. Airport (STL) to Colorado Springs Airport (COS). You can save 25% by booking your domestic flight 34 to 86 days in advance compared to last-minute reservations made 6 to 12 days out. You could also reduce costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get the timing right, and you can enjoy significant savings on domestic flights.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

Browse United Airlines's earliest flights from STL to COS by selecting the "Early Morning" and "Morning" filters. Not only will you get to where you're going sooner, early departures are also 20% less likely to be canceled.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

Travel from STL to COS with United Airlines and look forward to a range of benefits starting with a rewarding loyalty program. When booking through Expedia as a United Mileage Plus and One Key™ member, you may also earn OneKeyCash™* to use on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.