Carrier route record
DLATL→BOS
Delta Air Lines · Atlanta to Boston
- Flights
- 3,731
- Period
- September 2025 to August 2026
- Share of route
- 74%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on ATL to BOS sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 3,731 flights. The strongest carrier on the route with a full sample, JetBlue Airways, flew 857 at 69.2% on time.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on ATL to BOS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.4%
Arrivals under 15 minutes late, of 3,662 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
1.82%
National rate is 1.89%
Whole route
72.8%
Every carrier on ATL to BOS, 5,054 flights
These figures cover 3,731 flights between September 2025 and August 2026. Beyond the headline rate, 8.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Delta against every carrier on ATL to BOS
Delta flew 3,731 of the 5,054 flights on ATL to BOS, most of the route. Its 74.4% on time is 2 points better than the route as a whole, which runs 72.8%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Delta at 74.4% to Spirit at 61.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 3,731 | 74.4% | 61 min | 1.82% | C |
| JetBlue Airways | 857 | 69.2% | 92 min | 4.08% | C− |
| Frontier Airlines | 453 | 67.3% | 54 min | 2.87% | C |
| Spirit Airlinesthin sample | 13 | 61.5% | 57 min | 0.00% | D+ |
JetBlue Airways cancels 4.1% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Delta flight numbers on ATL to BOS
- DL 85509:1085.2% · 365 flights
- DL 86522:4080.2% · 360 flights
- DL 72613:4566.3% · 353 flights
- DL 82118:1569.2% · 349 flights
- DL 98707:2589.9% · 344 flights
- DL 35012:4074.6% · 339 flights
- DL 259514:5962.5% · 321 flights
- DL 30019:5968.8% · 298 flights
- DL 86211:1081.7% · 281 flights
- DL 51816:5252.7% · 279 flights
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 points, against 2 points between the best and worst carrier.
- 5am–8am358 flights90.3%
- 8am–11am665 flights88.2%
- 11am–2pm706 flights77.3%
- 2pm–5pm768 flights60.2%
- 5pm–8pm500 flights64.2%
- 8pm–5am734 flights73.1%
Scale runs 50% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.3% of the time, against 60.2% for the afternoon window. That is 30 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 768 flights scheduled in it.
Across the year
Delta on ATL to BOS through the year
July is the worst month at 62.2% on time, 18 points below June, the best at 79.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 353 flights.
Across the week, Saturday is the strongest day at 80.9% on time and Monday the weakest at 69.7%, a spread of 11 points.
Arrival by arrival
How late Delta on ATL to BOS runs when it is late
The 939 late arrivals split 325 under half an hour, 298 between 30 and 60 minutes, and 316 an hour or more.
- 15+ min early821 flights22.4%
- Within 15 min1,902 flights51.9%
- 15–29 min late325 flights8.9%
- 30–59 min late298 flights8.1%
- 1–2 hours late205 flights5.6%
- 2+ hours late111 flights3.0%
Scale runs 0% to 100%.
Share of 3,662 completed flights by arrival against schedule.
218 of 1,003 late departures made up the time and arrived on time, 22% of them. 154 flights left on time and still arrived late.
The worst days
Worst days for Delta on ATL to BOS
The latest arrival of the period was on 23 February 2026, 13 hours 33 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 23 February 2026 | 13 hours 33 minutes | Extreme weather |
| 11 November 2025 | 8 hours 26 minutes | Carrier |
| 24 February 2026 | 7 hours 34 minutes | Carrier |
| 16 March 2026 | 6 hours 7 minutes | Carrier |
| 7 December 2025 | 5 hours 54 minutes | Extreme weather |
Delay causes
Why Delta runs late on this route
National Airspace System accounts for 43% of the 57,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%National Airspace System
- 37%Carrier
- 15%Late-arriving aircraft
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 21,000 of the 57,000 delay minutes reported here. The split is drawn from 57,439 reported delay minutes.
43% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 25,000 minutes out of 57,000, against a national NAS share of 21%.
Cancellations sit at 1.82% against a national 1.89%, which is ordinary. Diversions add another 0.03%.
Connections and stage length
What a delay here costs
8.6% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
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.
The return leg is a different operation and performs like one: it runs 80.8% on time across 3,726 flights, 6 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.
The sample behind these figures is 3,731 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking Delta on ATL to BOS
Put together: the calendar is the biggest lever here, not the carrier or the hour. June runs 79.9% on time and July 62.2%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 3,662 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to BOS, every carrier
- Delta on BOS to ATL, the return leg
- JetBlue Airways on ATL to BOS69.2%
- Frontier Airlines on ATL to BOS67.3%
- Delta Air Lines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Boston Logan International (BOS) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
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.