St. Louis to Washington

What the Data Says About STL to DCA

The St. Louis to Washington corridor (STL → DCA) covers roughly 719 miles and is served by 25 carriers, based on Bureau of Transportation Statistics reporting. Across 12,061 flights in the dataset, this route posts a 80.4% on-time rate with an average delay of 70.5 minutes when flights run late. Over the most recent 24 months of BTS data, 4,651 flights were recorded on this pairing — 98 cancelled (2.1%) and 23 diverted (0.5%). Those baseline metrics tell you what to expect before you book.

Having 25 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 12,061 total flights analyzed, the 80.4% on-time figure is statistically meaningful rather than a small-sample fluke. The 70.5-minute average delay applies only to flights that actually ran late, so it is not the average wait across all departures — the majority of flights on this route depart on time under the BTS definition of a delay (15+ minutes past schedule).

Looking at recent months, Sep 2024 posted the best performance on this corridor at 93% on-time, while Feb 2025 came in at 60% on-time — a 33-point gap between best and worst recent month. For travelers evaluating the STL to DCA route, the combination of a 80.4% on-time rate, 70.5-minute average delay, 2.1% recent cancellation rate, and 25 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.