Flight profile · Delta Air Lines
DL1966
New York (JFK) to San Juan (SJU) · scheduled 8:00 AM – 12:00 PM
How DL1966 performs
359 operations, 2025-05-07 to 2026-06-30.
DL1966 arrived on time 83.3% of the time, against 71.0% for all JFK → SJU flights — this specific departure is 12.3 percentage points better than the route as a whole. Against Delta Air Lines’s own flights on this route it is 2.9 points better.
Source: US DOT Bureau of Transportation Statistics · 359 operations between 2025-05-07 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| DL1966 | 83.3% | 2.51% | -13 min | 3.7% | 359 |
| Delta Air Lines on JFK → SJU | 80.5% | 0.79% | -11 min | 6.2% | 3,309 |
| All JFK → SJU flights | 71.0% | 1.51% | -5 min | 11.5% | 11,028 |
Source: FlyerIntel analysis of US DOT BTS data · 2025-05-07 to 2026-06-30
Other routes DL1966 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
Because the same number has served different journeys, the statistics above describe only the route DL1966 currently operates. Blending them would produce an average of two different flights.
Why DL1966 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding, fuelling — within the carrier’s control
weather severe enough to stop this flight specifically
the inbound aircraft was late, so this flight started late
Share of the delay minutes US DOT attributed to each cause for DL1966 on JFK → SJU. A single late flight can carry more than one cause, and only delays of fifteen minutes or more are attributed at all.
Other departures on JFK → SJU
Same airports, same journey — and not the same odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL1877 | Delta Air Lines | 87.5% | 14 min early | 737 |
| DL1961 | Delta Air Lines | 87.3% | 15 min early | 1,051 |
| B61603 | JetBlue | 80.1% | 8 min early | 763 |
| B6503 | JetBlue | 74.9% | 5 min early | 986 |
| DL1859 | Delta Air Lines | 67.8% | 1 min early | 1,061 |
| B6803 | JetBlue | 64.9% | 0 min early | 917 |
| B61903 | JetBlue | 64.1% | 2 min late | 661 |
| B6403 | JetBlue | 62.8% | 2 min late | 737 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 359 records of DL1966 operating JFK → SJU, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.