Cheap flights from St. Louis to Ontario from $138

Travelers frequently search for route combinations, such as St. Louis and Las Vegas, Cancún, Orlando, Los Angeles, San Francisco, Denver, Mexico City, Tuxtla Gutiérrez, Toronto, Ottawa, Lima, Buenos Aires, Cali, Sydney, Warsaw, San José, Washington, D.C., Reykjavik, Fort Lauderdale, Melbourne.

Travelers frequently search for route combinations, such as Ontario and San Francisco, Las Vegas, Dallas, Guadalajara, Seattle, Sacramento, Houston, Portland, Denver, Atlanta, Chicago, New York, Los Angeles, Mexico City, Washington, D.C., Rome, Orlando, Columbus, Fargo, Raleigh.

The main airport in St. Louis is St. Louis Lambert International. It is also served by St. Louis Lambert International, General Wayne A. Downing Peoria International, Evansville Regional, Abraham Lincoln Capital, Central Illinois Regional, MidAmerica St. Louis, Waynesville-St. Robert Regional, Cape Girardeau Regional, Columbia Regional, Barkley Regional.

The main airport in Ontario is Ontario International. It is also served by Tijuana International, San Diego International, John Wayne, Ontario International, Hollywood Burbank, Palm Springs International, Long Beach, Santa Barbara Municipal, Imperial County, McClellan–Palomar.

Currently, you can fly between St. Louis and Ontario with Frontier Airlines, United Airlines, Alaska Airlines, Hawaiian Airlines, Spirit Airlines.

If you don’t have specific dates for your trip between St. Louis and Ontario, you can enter a date range into the departure and return fields. Most carriers on the Kiwi.com website allow you to search and book up to six months from the day of your search. Order the search results by the best, cheapest, or fastest route, or find the cheapest outbound and return combination in the pricing table.

Traveling between St. Louis and Ontario, you can choose between direct (nonstop) flights or flights with one or more stops. You can select the number of stops on your journey, including an overnight stopover, and the duration of the stopover. What’s more, you can also select where you want to have your stopover. Want to say "Hi" to a friend in another city en route to your destination? Or fancy a quick round of shopping? Go Multi-City or Nomad and add places to your search that you wish to visit.

There are a number of airports in and around St. Louis. The main one is St. Louis Lambert International and other nearby airports include St. Louis Lambert International, General Wayne A. Downing Peoria International, Evansville Regional, Abraham Lincoln Capital, Central Illinois Regional, MidAmerica St. Louis, Waynesville-St. Robert Regional, Cape Girardeau Regional, Columbia Regional, Barkley Regional

There are a number of airports in and around Ontario. The main one is Ontario International and other nearby airports include Tijuana International, San Diego International, John Wayne, Ontario International, Hollywood Burbank, Palm Springs International, Long Beach, Santa Barbara Municipal, Imperial County, McClellan–Palomar.