DL638
DL638 (Delta Air Lines) is a multi-stop service on 6 routes, busiest Boston to Atlanta. Of 577 departures recorded from October 2024 to July 2026, 76.1% left on time, according to the US BTS.
- On-time departures76.1%of 577 flights
- Average delay14.7 min
- July 202626▼ 16.1%vs July 2025
- Cancelled0.9%
- Legs flown under this number6
Recorded departures by month
All legs under this number combined; see the leg table.
The most recent periods19 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 10 | 31 | ▲ 210.0% |
| February | 20 | 11 | ▼ 45.0% |
| March | 31 | 21 | ▼ 32.3% |
| April | 28 | 21 | ▼ 25.0% |
| May | 30 | 29 | ▼ 3.3% |
| June | 30 | 27 | ▼ 10.0% |
| July | 31 | 26 | ▼ 16.1% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 30 | – | – |
| December | 31 | – | – |
| Year to date (Jan–Jul) | 180 | 166 | ▼ 7.8% |
according to the US BTS · October 2024 → July 2026
On-time departures by month
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods19 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 90.0% | 73.3% | ▼ 18.5% |
| February | 90.0% | 100.0% | ▲ 11.1% |
| March | 87.1% | 76.2% | ▼ 12.5% |
| April | 82.1% | 81.0% | ▼ 1.4% |
| May | 80.0% | 92.9% | ▲ 16.1% |
| June | 70.0% | 85.2% | ▲ 21.7% |
| July | 60.0% | 73.1% | ▲ 21.8% |
| August | 83.3% | – | – |
| September | 70.0% | – | – |
| October | 64.5% | – | in progress |
| November | 83.3% | – | – |
| December | 56.7% | – | – |
| Year-to-date average (Jan–Jul) | 79.9% | 83.1% | ▲ 4.0% |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
The most recent periods19 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 1 | – |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 0 | 1 | – |
| June | 0 | 0 | – |
| July | 1 | 0 | ▼ 100.0% |
| August | 1 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 1 | – | – |
| Year to date (Jan–Jul) | 1 | 2 | ▲ 100.0% |
according to the US BTS · October 2024 → July 2026
This is a historical record of departures already flown, not a forecast for your flight.
Several legs: the headline figure averages all of them. See the leg table.
Cancellation share
- Not cancelled 99.1% 572
- Cancelled 0.9% 5
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 31, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
2| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| BOS ATL Boston Logan International Airport – Hartsfield Jackson Atlanta International Airport | 1,521 | 15.9 min | 74.3% | 499 |
| BUF DTW Buffalo Niagara International Airport – Detroit Metropolitan Wayne County Airport | 387 | 16.1 min | 81.1% | 38 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 75.0% | 0 |
| November 2024 | 30 | 30 | 66.7% | 0 |
| December 2024 | 28 | 28 | 64.3% | 0 |
| January 2025 | 10 | 10 | 90.0% | 0 |
| February 2025 | 20 | 20 | 90.0% | 0 |
| March 2025 | 31 | 31 | 87.1% | 0 |
| April 2025 | 28 | 28 | 82.1% | 0 |
| May 2025 | 30 | 30 | 80.0% | 0 |
| June 2025 | 30 | 30 | 70.0% | 0 |
| July 2025 | 31 | 30 | 60.0% | 1 |
| August 2025 | 31 | 30 | 83.3% | 1 |
| September 2025 | 30 | 30 | 70.0% | 0 |
| October 2025 | 31 | 31 | 64.5% | 0 |
| November 2025 | 30 | 30 | 83.3% | 0 |
| December 2025 | 31 | 30 | 56.7% | 1 |
| January 2026 | 31 | 30 | 73.3% | 1 |
| February 2026 | 11 | 11 | 100.0% | 0 |
| March 2026 | 21 | 21 | 76.2% | 0 |
| April 2026 | 21 | 21 | 81.0% | 0 |
| May 2026 | 29 | 28 | 92.9% | 1 |
| June 2026 | 27 | 27 | 85.2% | 0 |
| July 2026 | 26 | 26 | 73.1% | 0 |