$169 Cheap United flights Ontario (ONT) to Baltimore (BWI)

Scoring cheap one-way United Airlines flights from ONT to BWI from $169 on Expedia couldn't be easier — just filter by "Price (lowest to highest)." Or check out our affordable round-trip fares from $239 for your next exciting adventure.**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.

To find cheap United Airlines fares from Los Angeles - Ontario Intl. Airport (ONT) to Baltimore Washington Intl. Thurgood Marshall Airport (BWI), start searching one to three months before your planned departure. Reserving domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also affect the cost. Sunday tends to be the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by choosing to book on a Sunday.**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 ONT to BWI with United Airlines, filter your results by "Early Morning" and "Morning." Booking an early flight usually means cancellations are less likely.**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.

With a rewarding loyalty program, United Airlines is a favorite of many passengers departing from ONT to BWI. Plus, if you're a United Mileage Plus and One Key™ member booking through Expedia, you can 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.