Route reliability record
FLL→BOS
Fort Lauderdale to Boston
- Flights
- 3,293
- Period
- September 2025 to August 2026
- Distance
- 1,237 mi
- Carriers
- 3
This route carries a cancellation problem, not just a delay problem: 3.7% of scheduled flights never operate, against 1.9% nationally. Of the ones that do fly, about two flights in three arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 3,293 FLL to BOS flights, of which Delta Air Lines flew 886 at 72.1% on time.
Best time to fly FLL to BOS: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 85.5% of the time and Wednesday flights 75.1%, against 66.8% for the route overall.
Delta Air Lines is the most reliable of the three carriers covered here at 72.1% on time across 886 flights.
Key figures
On time
66.8%
Arrivals under 15 minutes late, of 3,168 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
3.67%
National rate is 1.89%
Best carrier
Delta
72.1% on time across 886 flights
These figures cover 3,293 flights between September 2025 and August 2026. Beyond the headline rate, 14.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on FLL to BOS
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 72.1% of the time; Spirit Airlines manages 60.0%. Sample sizes sit next to every figure, because a two-point gap across 447 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 886 | 72.1% | 78 min | 3.16% | C− |
| JetBlue Airways | 1,960 | 65.9% | 76 min | 3.37% | C− |
| Spirit Airlines | 447 | 60.0% | 77 min | 6.04% | D− |
Spirit Airlines cancels 6.0% 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
Flights on FLL to BOS
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Fort Lauderdale to Boston
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MIA → BOSMiami to Boston | American Airlines | 69.9% | 71.1% | 1.67% | 5am–8am, Sat | AA 1074 17:35 |
| 2. FLL → BOSFort Lauderdale to Boston | Delta Air Lines | 69.8% | 72.1% | 3.16% | 5am–8am, Sat | — |
| 3. MIA → BOSMiami to Boston | Delta Air Lines | 67.7% | 69.6% | 2.70% | 5am–8am, Tue | — |
| 4. PBI → BOSWest Palm Beach to Boston | Delta Air Lines | 63.9% | 66.2% | 3.42% | 11am–2pm, Sat | — |
| 5. FLL → BOSFort Lauderdale to Boston | JetBlue Airways | 63.7% | 65.9% | 3.37% | 5am–8am, Wed | B6 470 20:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against 12 points between the best and worst carrier.
- 5am–8am575 flights85.5%
- 8am–11am331 flights83.1%
- 11am–2pm672 flights63.6%
- 2pm–5pm443 flights55.3%
- 5pm–8pm398 flights53.9%
- 8pm–5am874 flights62.0%
Scale runs 45% to 90%.
The 5pm–8pm window is where this operation falls apart: 53.9% on time, against 85.5% 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 8pm–5am window is the busiest, with 874 flights scheduled in it.
Explore
Filter FLL to BOS by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On FLL to BOS, the best departure window is 5am–8am at 85.5% on time and the worst is 5pm–8pm at 53.9%, a wide gap of 31.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am85.5%
- 8–11am83.1%
- 11am–2pm63.6%
- 2–5pm55.3%
- 5–8pm53.9%
- 8pm–5am62.0%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 24 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 57.1% on time, 24 points below May, the best at 81.6%. 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. March was the busiest month here, with 387 flights.
Across the week, Wednesday is the strongest day at 75.1% on time and Sunday the weakest at 57.4%, a spread of 18 points.
Delay causes
Why this route gets delayed
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 81,000 reported delay minutes.
- 36%Late-arriving aircraft
- 30%National Airspace System
- 30%Carrier
- 3%Extreme weather
- 0%Security
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 81,000 reported delay minutes here, that single category outweighs weather by 14 to one. The split is drawn from 80,720 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 85.5% on time here.
Cancellations run at 3.67%, against 1.89% nationally. That is roughly one flight in 25 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 actually costs
14.9% 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.
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.
The return leg runs 66.8% on time across 3,306 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 3,293 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.
Work out the risk of missing a connection in BOS after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.67% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 3,168 completed flights over 12 months sit behind that.
Common questions
FLL to BOS questions
How often is FLL to BOS delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 33.2% of the 3,293 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 FLL to BOS?
Delta Air Lines leads at 72.1% on time across 886 flights. Spirit Airlines is at the other end on 60.0%, a gap of 12 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 FLL to BOS?
The 5am–8am departure window is the strongest at 85.5% on time. The 5pm–8pm window is the weakest at 53.9%, 32 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 July delays on FLL to BOS?
July is the weakest month at 57.1% on time, compared with 81.6% in May. Across the year that is 24 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
- BOS to FLL — the return legseparate record
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- Boston Logan International (BOS) delay statistics
- Delta Air Lines on FLL to BOS72.1%
- JetBlue Airways on FLL to BOS65.9%
- Spirit Airlines on FLL to BOS60.0%
- FLL to ATL, a related route71.0%
- DCA to BOS, a related route70.1%
- FLL to LGA, a related route64.8%
- Delta Air Lines on-time record72.1%
- JetBlue Airways on-time record65.9%
- Spirit Airlines on-time record60.0%
- The US routes with the most cancellations
- Same route, different airline: where the carrier you pick matters most
Direction matters. FLL to BOS and BOS to FLL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.