Flight number record
DL 456
Delta Air Lines · Boston to Atlanta
- Route
- BOS → ATL
- Departs
- 09:05
- Flights
- 359
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 456, check with Delta Air Lines.
DL 456 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 359 flights, with a median arrival 12 minutes early.
Set against the rest of the country, DL 456's record is 12 points better than the US average of 77.3%. That gap is worth roughly 121 fewer late arrivals for every thousand flights.
Key figures
On time
89.4%
Arrivals under 15 minutes late, of 349 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
2.51%
National rate is 1.89%
1 hour+ late
2.9%
National rate is 8.3%
These figures cover 359 flights between September 2025 and August 2026. The median arrival is 12 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When DL 456 flies
DL 456 flies BOS to ATL without a single fixed slot. Its most common scheduled departure was 09:05, used on 117 of 359 flights, with 08:30 (60 flights) and 08:00 (47 flights) next.
- Departs 09:05117 flights32.6%
- Departs 08:3060 flights16.7%
- Departs 08:0047 flights13.1%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 09:05 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 456 runs 6 points better at 89.4%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 456 next to BOS to ATL
Every carrier on BOS to ATL combined arrived on time 76.8% of the time across 5,050 flights, so DL 456 is 13 points ahead of it. Delta flew 3,726 flights on the same city pair under all its flight numbers, including this one, and those ran 80.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 8 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 456thin sample | 359 | 89.4% | 74 min | 2.51% | A |
| All Delta Air Lines on BOS–ATL | 3,726 | 80.8% | 75 min | 1.85% | B |
| All carriers on BOS–ATL | 5,050 | 76.8% | 72 min | 2.24% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 456 quarter by quarter
DL 456 did not run the same all year. Its best quarter was Apr–Jun 2026 at 95.6% on time and its weakest Jan–Mar 2026 at 83.3%, a swing of 12 points on roughly 72 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights90.0%
- Oct–Dec 202586 flights86.9%
- Jan–Mar 202690 flights83.3%
- Apr–Jun 202691 flights95.6%
- Jul–Sep 202662 flights91.8%
Scale runs 75% to 100%.
By weekday, DL 456 ranged from 82.7% on Sunday to 94.2% on Thursday. With about 51 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 456 runs when it is late
DL 456 often beats the schedule: 134 of 349 completed flights, 38%, arrived 15 minutes or more early. The 37 late arrivals split 15 under half an hour, 12 between 30 and 60 minutes, and 10 an hour or more.
- 15+ min early134 flights38.4%
- Within 15 min178 flights51.0%
- 15–29 min late15 flights4.3%
- 30–59 min late12 flights3.4%
- 1–2 hours late4 flights1.1%
- 2+ hours late6 flights1.7%
Scale runs 0% to 100%.
Share of 349 completed flights by arrival against schedule.
6 of 26 late departures made up the time and arrived on time, 23% of them. 17 flights left on time and still arrived late.
The worst days
Worst days for DL 456
The latest arrival of the period was on 18 October 2025, 9 hours 3 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 18 October 2025 | 9 hours 3 minutes | Carrier |
| 21 December 2025 | 5 hours 13 minutes | Carrier |
| 7 December 2025 | 4 hours 6 minutes | National Airspace System |
| 29 December 2025 | 4 hours 4 minutes | Carrier |
| 19 January 2026 | 2 hours 44 minutes | National Airspace System |
Delay causes
Why DL 456 runs late
Carrier accounts for 58% of the 2,734 delay minutes carriers reported here, and the remaining four split what is left.
- 58%Carrier
- 35%National Airspace System
- 5%Late-arriving aircraft
- 3%Extreme weather
The largest share of delay minutes, 58%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,575 of the 2,734 delay minutes reported here. The split is drawn from 2,734 delay minutes reported on DL 456.
Cancellations run at 2.51%, against 1.89% nationally. That is about one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 2.9% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 946 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
Every one of the 359 flights under DL 456 in the data flew BOS to ATL. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 359 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 456
For a booking, the cancellation rate is the figure to plan around on DL 456: 2.51% of its 359 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- BOS to ATL, every carrier and departure
- ATL to BOS, the return direction
- Delta Air Lines 695 on the same route86.0%
- Delta Air Lines 322 on the same route78.0%
- Delta Air Lines 973 on the same route79.1%
- Delta Air Lines 385 on the same route86.4%
- Delta Air Lines 923 on the same route87.2%
- Delta Air Lines 2464 on the same route74.9%
- Boston Logan International (BOS) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- What a cancellation rate actually tells you (and what it hides)
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.