Carrier route record
DLBOS→FLL
Delta Air Lines · Boston to Fort Lauderdale
- Flights
- 885
- Period
- July 2025 to June 2026
- Share of route
- 26%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on BOS to FLL sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 885 flights. The strongest carrier on the route with a full sample, JetBlue Airways, flew 1,961 at 66.1% on time.
The national on-time rate over the same period is 77.6%, so Delta on BOS to FLL runs 8 points behind the country as a whole. Across a thousand flights that is about 81 extra late arrivals.
Key figures
On time
69.5%
Arrivals under 15 minutes late, of 853 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
3.05%
National rate is 1.81%
Whole route
66.7%
Every carrier on BOS to FLL, 3,417 flights
These figures cover 885 flights between July 2025 and June 2026. Beyond the headline rate, 13.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Delta against every carrier on BOS to FLL
Delta flew 885 of the 3,417 flights on BOS to FLL, about 26% of it. Its 69.5% on time is 3 points better than the route as a whole, which runs 66.7%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from Delta at 69.5% to Spirit at 64.6%.
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) | 885 | 69.5% | 78 min | 3.05% | C− |
| JetBlue Airways | 1,961 | 66.1% | 69 min | 3.16% | C− |
| Spirit Airlines | 571 | 64.6% | 82 min | 5.08% | D− |
Spirit Airlines cancels 5.1% 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 BOS to FLL
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. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am271 flights80.8%
- 8am–11am94 flights85.9%
- 11am–2pm21 flights—
- 2pm–5pm341 flights61.4%
- 5pm–8pm52 flights56.0%
- 8pm–5am106 flights65.0%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 56.0% on time, against 85.9% for the 8am–11am 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 2pm–5pm window is the busiest, with 341 flights scheduled in it.
Across the year
Delta on BOS to FLL through the year
December is the weak month at 52.9% on time, against 80.0% in August. 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. December was the busiest month here, with 90 flights.
Across the week, Wednesday is the strongest day at 77.4% on time and Thursday the weakest at 64.3%. 13 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 20,000 reported delay minutes.
- 42%Late-arriving aircraft
- 30%National Airspace System
- 27%Carrier
- 1%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 20,000 reported delay minutes here, that single category outweighs weather by 34 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 20,233 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 85.9% on time here.
Cancellations run at 3.05%, against 1.81% nationally. That is roughly one flight in 30 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 stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 13.1% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 1,237 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 71.8% on time across 884 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 885 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 Delta on BOS to FLL
Put together: the delay figures matter less here than the 3.05% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 853 completed flights over 12 months sit behind that.
Related
Where to go next
- BOS to FLL, every carrier
- Delta on FLL to BOS, the return leg
- JetBlue Airways on BOS to FLL66.1%
- Spirit Airlines on BOS to FLL64.6%
- Delta Air Lines network-wide record
- Boston Logan International (BOS) delay statistics
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.