Baltimore to Islip

What the Data Says About BWI to ISP

The Baltimore to Islip corridor (BWI → ISP) covers roughly 220 miles and is served by 1 carrier, based on Bureau of Transportation Statistics reporting. Across 7,398 flights in the dataset, this route posts a 76.7% on-time rate with an average delay of 55.3 minutes when flights run late. Over the most recent 24 months of BTS data, 2,457 flights were recorded on this pairing — 26 cancelled (1.1%) and 5 diverted (0.2%). 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 7,398 total flights analyzed, the 76.7% on-time figure is statistically meaningful rather than a small-sample fluke. The 55.3-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, Feb 2025 posted the best performance on this corridor at 90% on-time, while Jul 2024 came in at 61% on-time — a 29-point gap between best and worst recent month. For travelers evaluating the BWI to ISP route, the combination of a 76.7% on-time rate, 55.3-minute average delay, 1.1% recent cancellation rate, and 1 available carrier is the concrete summary of what BTS data shows about reliability on this pairing.