Chicago to St. Louis

What the Data Says About ORD to STL

The Chicago to St. Louis corridor (ORD → STL) covers roughly 258 miles and is served by 40 carriers, based on Bureau of Transportation Statistics reporting. Across 13,359 flights in the dataset, this route posts a 79.7% on-time rate with an average delay of 73.2 minutes when flights run late. Over the most recent 24 months of BTS data, 5,546 flights were recorded on this pairing — 84 cancelled (1.5%) and 8 diverted (0.1%). Those baseline metrics tell you what to expect before you book.

Having 40 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 13,359 total flights analyzed, the 79.7% on-time figure is statistically meaningful rather than a small-sample fluke. The 73.2-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, Oct 2024 posted the best performance on this corridor at 90% on-time, while Dec 2025 came in at 61% on-time — a 29-point gap between best and worst recent month. For travelers evaluating the ORD to STL route, the combination of a 79.7% on-time rate, 73.2-minute average delay, 1.5% recent cancellation rate, and 40 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.