Islip (ISP) departure delays
4,986 departures · 8 routes · January 2025 – August 2026
75.29%
Left on time
Within 15 minutes of schedule
1.97%
Cancelled
Share of departures
71 min
When late, late by
Average delayed departure
#212
Rank
Among graded US airports
What the record says about ISP
Departures from Islip run late more often than average — enough that a tight connection at the far end deserves a second look.
The airlines flying from here are not equally affected. Southwest Airlines left on time 6.8 points more often than JetBlue Airways from the same airport — which is the clearest evidence available that a delayed departure is not purely the airport's fault.
Which airlines run best out of ISP
| Airline | Departures | On time |
|---|---|---|
| Southwest Airlines | 2,642 | 78.1% |
| Frontier Airlines | 873 | 73% |
| JetBlue Airways | 1,471 | 71.3% |
Routes out of ISP
Common questions
How bad are delays at Islip (ISP)?
75.29% of departures from ISP left within 15 minutes of schedule across 4,986 flights. That is about average.
Which airline is most punctual from ISP?
Southwest Airlines, at 78.1% on time from this airport. The least punctual was JetBlue Airways at 71.3%.
How often are flights from ISP cancelled?
1.97% of scheduled departures did not operate.