$90 Cheap American Airlines flights Washington (DCA) to St. Louis (STL)

Scoring cheap one-way American Airlines flights from DCA to STL from $90 on Expedia is simple --- just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly round-trip fares from $179 for your next break.**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.

Search for cheap American Airlines flights from Ronald Reagan Washington National Airport (DCA) to Lambert-St. Louis Intl. Airport (STL) one to three months ahead of your day of 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 class and journey, the ideal day to book a domestic flight is generally Sunday and the most expensive 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.

The first American Airlines flight from DCA to STL takes off at 8:37AM UTC-5, landing at 10:24AM UTC-6. If you want to head off later, the last American Airlines flight leaves DCA at 10:04PM UTC-5 and touches down at STL at 11:53PM UTC-6. Flying early is generally a smart option as morning flights are 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.