Islip to Baltimore

What the Data Says About ISP to BWI

The Islip to Baltimore corridor (ISP → BWI) covers roughly 220 miles and is served by 1 carrier, based on Bureau of Transportation Statistics reporting. Across 7,390 flights in the dataset, this route posts a 88.3% on-time rate with an average delay of 69.7 minutes when flights run late. Over the most recent 24 months of BTS data, 2,456 flights were recorded on this pairing — 19 cancelled (0.8%) and 3 diverted (0.1%). 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 7,390 total flights analyzed, the 88.3% on-time figure is statistically meaningful rather than a small-sample fluke. The 69.7-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 2025 posted the best performance on this corridor at 96% on-time, while Jul 2025 came in at 75% on-time — a 21-point gap between best and worst recent month. For travelers evaluating the ISP to BWI route, the combination of a 88.3% on-time rate, 69.7-minute average delay, 0.8% recent cancellation rate, and 1 available carrier is the concrete summary of what BTS data shows about reliability on this pairing.