Flight profile · Delta Air Lines
DL1399
Boston (BOS) to Miami (MIA) · scheduled 7:05 AM – 10:35 AM
How DL1399 performs
1,000 operations, 2023-07-01 to 2026-06-30.
DL1399 arrived on time 84.2% of the time, against 78.1% for all BOS → MIA flights — this specific departure is 6.1 percentage points better than the route as a whole. Against Delta Air Lines’s own flights on this route it is 11.0 points better.
Source: US DOT Bureau of Transportation Statistics · 1,000 operations between 2023-07-01 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| DL1399 | 84.2% | 1.00% | -10 min | 5.0% | 1,000 |
| Delta Air Lines on BOS → MIA | 73.2% | 1.52% | -5 min | 10.6% | 2,307 |
| All BOS → MIA flights | 78.1% | 1.56% | -9 min | 8.3% | 11,209 |
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30
By day of week
Does DL1399 run worse on particular days?
Tuesday is historically the most reliable day and Friday the least, a gap of 8.2 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30 · Days with fewer than 120 operations are not scored.
Other routes DL1399 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 DL1399 currently operates. Blending them would produce an average of two different flights.
Data and methodology
Calculated by FlyerIntel from 1,000 records of DL1399 operating BOS → MIA, 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.