Seattle to Billings

What the Data Says About SEA to BIL

The Seattle to Billings corridor (SEA → BIL) covers roughly 664 miles and is served by 1 carrier, based on Bureau of Transportation Statistics reporting. Across 1,691 flights in the dataset, this route posts a 85.8% on-time rate with an average delay of 56.0 minutes when flights run late. Over the most recent 24 months of BTS data, 1,691 flights were recorded on this pairing — 21 cancelled (1.2%) and 6 diverted (0.4%). Those baseline metrics tell you what to expect before you book.

Having 1 carrier on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 1,691 total flights analyzed, the 85.8% on-time figure is statistically meaningful rather than a small-sample fluke. The 56.0-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, Apr 2021 posted the best performance on this corridor at 97% on-time, while Dec 2022 came in at 68% on-time — a 29-point gap between best and worst recent month. For travelers evaluating the SEA to BIL route, the combination of a 85.8% on-time rate, 56.0-minute average delay, 1.2% recent cancellation rate, and 1 available carrier is the concrete summary of what BTS data shows about reliability on this pairing.