Flight profile · Delta Air Lines
DL977
Boston (BOS) to San Francisco (SFO) · scheduled 7:55 AM – 11:37 AM
How DL977 performs
862 operations, 2023-07-01 to 2026-06-30.
DL977 arrived on time 80.8% of the time, against 75.0% for all BOS → SFO flights — this specific departure is 5.9 percentage points better than the route as a whole. Against Delta Air Lines’s own flights on this route it is 7.1 points better.
Source: US DOT Bureau of Transportation Statistics · 862 operations between 2023-07-01 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| DL977 | 80.8% | 0.70% | -8 min | 4.9% | 862 |
| Delta Air Lines on BOS → SFO | 73.7% | 0.91% | -6 min | 7.8% | 2,425 |
| All BOS → SFO flights | 75.0% | 0.96% | -6 min | 8.6% | 13,723 |
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30
By day of week
Does DL977 run worse on particular days?
Thursday is historically the most reliable day and Friday the least, a gap of 9.3 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 DL977 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.
| Route | Operated | Flights | On time |
|---|---|---|---|
| SFO→BOS San Francisco to Boston | 2023-07-01 – 2026-06-30 | 798 | 72.5% |
| MCO→ATL Orlando to Atlanta | 2025-08-11 – 2025-12-19 | 130 | 64.3% |
| DSM→ATL Des Moines to Atlanta | 2025-06-14 – 2025-08-09 | 15 | — |
| ATL→DSM Atlanta to Des Moines | 2025-07-12 – 2025-08-09 | 5 | — |
| SRQ→ATL Sarasota/Bradenton to Atlanta | 2024-12-21 – 2025-01-04 | 3 | — |
Because the same number has served different journeys, the statistics above describe only the route DL977 currently operates. Blending them would produce an average of two different flights.
Data and methodology
Calculated by FlyerIntel from 862 records of DL977 operating BOS → SFO, 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.