$34 Cheap flight deals from Denver (DEN) to Union (STL)

Orbitz has your best deals on Denver to Union flights. From guaranteed low prices to cutting-edge mobile tools, the perfect trip begins on Orbitz.
Get Orbitz On the Go for Flights from Denver to Union
Use our mobile apps for Android and iPhone to find the best price on flights from Denver to Union. Check your flight status, gate and baggage claim details, and book exclusive mobile deals on hotels — even on the same day.

Rack Up Miles While Flying for Cheaper

Earn miles or points toward your frequent flyer program on select Denver to Union flights. When you book your flight on Orbitz, simply add your qualifying frequent flyer number where prompted. You can also store your airline frequent flyer or loyalty program numbers in your Orbitz account profile to automatically add them to your future reservations.

Worry Less With Flight Alerts

Orbitz is the best source for booking flights from Denver to Union. But we also keep you updated about flight delays, booking changes, or service disruptions with free alerts. Get alerts on Denver to Union flights sent to your email or via voice or text to your mobile phone. We can also send the alerts to up to 6 other email addresses or phone numbers, which is helpful if you are being picked up at the airport.

Budget Travel Planning Made Easy

It's easy to find discount air tickets for flights from Denver to Union on Orbitz. Mix and match airlines for your departing and your returning flights to find the lowest fares and the best schedule.