Carrier performance at one airport
DL→BOS
Delta Air Lines at Boston Logan International
- Departures
- 26,567
- Period
- September 2025 to August 2026
- Routes
- 25
- Rank here
- #6 of 11
Delta Air Lines at Boston lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 26,567 flights, of which Allegiant Air flew 586 at 82.1% on time.
Measured against the airport rather than the country, Delta Air Lines runs about a point ahead of the 74.6% weighted average across all carriers at BOS. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
76.0%
25,920 completed departures
Avg delay
73 min
Across delayed flights only
Cancelled
2.16%
At BOS, this carrier only
Rank here
#6
Of 11 carriers clearing the floor at BOS
These figures cover 27,000 flights between September 2025 and August 2026. Beyond the headline rate, 9.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Against the competition
Every carrier at BOS, ranked
The choice of carrier is not cosmetic here. Allegiant Air arrives on time 82.1% of the time; Spirit Airlines manages 61.6%. Sample sizes sit next to every figure, because a two-point gap across 1,737 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Allegiant Air | 586 | 82.1% | 79 min | 0.68% | B+ |
| Envoy Air | 2,055 | 79.1% | 86 min | 2.29% | B |
| American Airlines | 17,138 | 78.2% | 93 min | 2.54% | B |
| United Airlines | 13,042 | 77.7% | 78 min | 1.92% | B |
| Republic Airways | 34,798 | 77.2% | 68 min | 4.38% | B− |
| Delta Air Lines (this page) | 26,567 | 76.0% | 73 min | 2.16% | B |
| Alaska Airlines | 2,420 | 71.4% | 57 min | 1.36% | C |
| JetBlue Airways | 37,517 | 70.1% | 71 min | 3.41% | C− |
| Southwest Airlines | 7,340 | 69.3% | 62 min | 1.66% | C |
| Frontier Airlines | 926 | 68.0% | 65 min | 1.84% | C |
| Spirit Airlines | 1,737 | 61.6% | 80 min | 5.87% | D− |
Spirit Airlines cancels 5.9% 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.
Route by route
Where Delta Air Lines flies from BOS
Delta Air Lines operates 25 routes out of BOS with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| BOS to ATL · Atlanta | 3,726 | 80.8% | 75 min | 1.85% | B |
| BOS to MSP · Minneapolis | 1,853 | 82.0% | 70 min | 1.35% | B |
| BOS to DTW · Detroit | 1,718 | 78.1% | 79 min | 2.21% | B |
| BOS to RDU · Raleigh | 1,436 | 77.1% | 85 min | 2.65% | B |
| BOS to MCO · Orlando | 1,257 | 75.5% | 79 min | 2.23% | B |
| BOS to LAX · Los Angeles | 1,238 | 73.9% | 74 min | 2.18% | C |
| BOS to TPA · Tampa | 1,169 | 76.3% | 73 min | 2.05% | B |
| BOS to SLC · Salt Lake City | 1,083 | 77.5% | 67 min | 1.20% | B |
| BOS to SEA · Seattle | 1,068 | 71.1% | 57 min | 1.59% | C |
| BOS to AUS · Austin | 1,001 | 73.7% | 87 min | 2.60% | C |
| BOS to ORD · Chicago | 981 | 63.7% | 75 min | 3.47% | D− |
| BOS to SFO · San Francisco | 945 | 69.0% | 63 min | 1.59% | C |
| BOS to MIA · Miami | 892 | 72.4% | 78 min | 2.58% | C |
| BOS to FLL · Fort Lauderdale | 887 | 69.8% | 76 min | 3.04% | C− |
| BOS to DFW · Dallas-Fort Worth | 868 | 72.7% | 77 min | 2.19% | C |
| BOS to BNA · Nashville | 558 | 68.1% | 88 min | 1.61% | C |
| BOS to LAS · Las Vegas | 551 | 77.5% | 59 min | 1.27% | B |
| BOS to RSW · Fort Myers | 549 | 79.5% | 65 min | 1.28% | B |
| BOS to PBI · West Palm Beach | 527 | 69.0% | 78 min | 2.85% | C |
| BOS to LGA · New York | 471 | 90.8% | 123 min | 4.88% | A− |
| BOS to PHX · Phoenix | 429 | 71.5% | 53 min | 1.86% | C |
| BOS to SJU · San Juan | 398 | 74.5% | 57 min | 1.51% | C |
| BOS to MSY · New Orleans | 374 | 82.7% | 70 min | 2.14% | B |
| BOS to CHS · Charleston | 370 | 76.2% | 71 min | 3.24% | B− |
| BOS to JFK · New York | 368 | 91.6% | 75 min | 3.26% | A− |
Flight by flight
Delta Air Lines flight numbers from BOS
55 Delta Air Lines flight numbers leaving BOS flew their main route often enough to have a record of their own. Grouped by destination.
- DL 322to ATL 14:0078.0%
- DL 385to ATL 09:0586.4%
- DL 456to ATL 09:0589.4%
- DL 638to ATL 15:1076.6%
- DL 695to ATL 05:3586.0%
- DL 923to ATL 06:5587.2%
- DL 973to ATL 11:1579.1%
- DL 2464to ATL 18:3574.9%
- DL 1297to AUS 13:2574.3%
- DL 1410to AUS 06:0583.6%
- DL 1677to AUS 17:4561.7%
- DL 2785to CHS 12:5576.2%
- DL 499to DEN 07:4583.6%
- DL 760to DFW 07:1578.6%
- DL 2305to DFW 18:2066.5%
- DL 1019to DTW 05:3094.1%
- DL 1432to DTW 17:1568.6%
- DL 1748to DTW 09:0086.9%
- DL 2222to DTW 13:1080.7%
- DL 1401to FLL 07:1082.1%
- DL 2196to FLL 15:5561.3%
- DL 2611to JFK 06:0092.3%
- DL 497to LAS 07:5081.4%
- DL 318to LAX 16:3070.8%
- DL 321to LAX 20:3565.8%
- DL 479to LAX 06:1578.4%
- DL 1513to MCO 20:2065.8%
- DL 1580to MCO 07:0590.7%
- DL 776to MIA 15:2063.1%
- DL 1399to MIA 07:0584.0%
- DL 1098to MSP 18:1570.6%
- DL 1103to MSP 11:5083.8%
- DL 1127to MSP 15:1572.7%
- DL 2303to MSP 05:5093.6%
- DL 1398to MSY 11:2082.5%
- DL 2570to ORD 07:3080.5%
- DL 2646to ORD 16:1559.3%
- DL 2160to PBI 15:3560.4%
- DL 514to PHX 17:5571.2%
- DL 817to RDU 20:0554.1%
- DL 2066to RDU 06:3090.3%
- DL 2118to RDU 10:0088.3%
- DL 2782to RDU 16:3572.6%
- DL 2474to RSW 07:3087.6%
- DL 571to SAN 17:1066.0%
- DL 2652to SAT 09:1579.6%
- DL 324to SEA 18:4564.8%
- DL 384to SEA 07:1574.3%
- DL 1655to SFO 17:0566.1%
- DL 1780to SJU 08:0576.5%
- DL 445to SLC 18:4569.4%
- DL 464to SLC 10:2076.2%
- DL 859to SLC 06:1087.2%
- DL 1439to TPA 15:4071.6%
- DL 2234to TPA 19:3063.4%
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against 20 points between the best and worst carrier.
- 5am–8am7,296 flights86.1%
- 8am–11am4,437 flights81.0%
- 11am–2pm4,053 flights79.0%
- 2pm–5pm4,183 flights68.4%
- 5pm–8pm4,721 flights67.2%
- 8pm–5am1,877 flights58.1%
Scale runs 50% to 90%.
The 8pm–5am window is where this operation falls apart: 58.1% on time, against 86.1% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 7,296 flights scheduled in it.
Across the year
Seasonal pattern
December is the weak month at 66.9% on time, against 81.3% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. August was the busiest month here, with 2,403 flights.
Delay causes
What holds this operation up
- 37%Carrier
- 37%Late-arriving aircraft
- 24%National Airspace System
- 1%Extreme weather
- 0%Security
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 456,000 reported delay minutes here, that single category outweighs weather by 28 to one. The split is drawn from 456,025 reported delay minutes.
Cancellations sit at 2.16% against a national 1.89%, which is ordinary. Diversions add another 0.27%.
9.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
26,567 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 81.3% on time and December 66.9%, a swing of 14 points. If the dates move at all, move them out of December before you think about anything else. 25,920 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at BOS
How often is Delta Air Lines at BOS delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.0% of the 26,567 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on Delta Air Lines at BOS?
Allegiant Air leads at 82.1% on time across 586 flights. Spirit Airlines is at the other end on 61.6%, a gap of 20 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Delta Air Lines at BOS?
The 5am–8am departure window is the strongest at 86.1% on time. The 8pm–5am window is the weakest at 58.1%, 28 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on Delta Air Lines at BOS?
December is the weakest month at 66.9% on time, compared with 81.3% in April. Across the year that is 14 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
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.