$147 Cheap American Airlines flights Chicago (ORD) to Ontario (ONT)

Set the "Price (lowest to highest)" filter on Expedia to find cheap American Airlines round-trip flights from $274 from ORD to ONT. Affordable one-way tickets from $147 are also available.**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.

Look for cheap American Airlines flights from O'Hare Intl. Airport (ORD) to Los Angeles - Ontario Intl. Airport (ONT) one to three months prior to your departure. Travelers who book domestic flights 34 to 86 days in advance can save 25% compared to those who book just 6 to 12 days ahead. No matter the fare type and journey, the best day to book a domestic flight is generally Sunday and the most expensive day is typically Monday. Passengers who book on a Sunday can save 6% on average compared to those who book on a Monday.**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.

To find the earliest departure from ORD to ONT with American Airlines, sort your results by "Early Morning" and "Morning." Booking an early flight usually means you're less likely to experience cancellations.**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.