$65 Cheap Frontier Airlines flights Atlanta (ATL) to Ontario (ONT)

Scoring cheap one-way Frontier Airlines flights from ATL to ONT from $65 on Expedia is a cinch — just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly round-trip fares from $134 for your next exciting vacation.**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.

Begin your search one to three months ahead of your travel date to score cheap fares on Frontier Airlines flights from Hartsfield-Jackson Atlanta Intl. Airport (ATL) to Los Angeles - Ontario Intl. Airport (ONT). 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 cut 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 journeys.*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 Frontier Airlines's earliest flights from ATL to ONT by using our "Early Morning" and "Morning" filters. Not only will you arrive at your destination 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.

Offering a rewarding loyalty program, Frontier Airlines is a top choice for many travelers departing from ATL to ONT. Plus, as a Frontier Miles and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.