Route reliability record
IAH→FLL
Houston to Fort Lauderdale
- Flights
- 2,923
- Period
- September 2025 to August 2026
- Distance
- 966 mi
- Carriers
- 4
This route lands a B, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,923 IAH to FLL flights, of which United Airlines flew 1,893 at 85.6% on time.
Best time to fly IAH to FLL: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 80.1% of the time and Tuesday flights 86.4%, against 78.5% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.5%
Arrivals under 15 minutes late, of 2,883 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
1.27%
National rate is 1.89%
Best carrier
United
85.6% on time across 1,893 flights
These figures cover 2,923 flights between September 2025 and August 2026. Beyond the headline rate, 8.3% 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 IAH to FLL
The choice of carrier is not cosmetic here. United Airlines arrives on time 85.6% of the time; Spirit Airlines manages 70.9%. Sample sizes sit next to every figure, because a two-point gap across 704 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,893 | 85.6% | 59 min | 0.58% | A+ |
| Spirit Airlines | 704 | 70.9% | 77 min | 1.99% | C |
| Frontier Airlinesthin sample | 165 | 61.6% | 52 min | 3.64% | D− |
| JetBlue Airwaysthin sample | 161 | 43.9% | 77 min | 3.73% | F− |
The spread between United and Spirit is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.
Flight by flight
Flights on IAH to FLL
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 Houston to Fort Lauderdale
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. IAH → FLLHouston to Fort Lauderdale | United Airlines | 85.1% | 85.6% | 0.58% | 5am–8am, Tue | UA 2261 07:20 |
| 2. IAH → MIAHouston to Miami | United Airlines | 81.8% | 82.0% | 0.28% | 5am–8am, Tue | UA 410 12:00 |
| 3. IAH → MIAHouston to Miami | American Airlines | 77.8% | 78.8% | 1.21% | 5am–8am, Wed | AA 1347 07:30 |
| 4. IAH → FLLHouston to Fort Lauderdale | Spirit Airlines | 69.5% | 70.9% | 1.99% | 5am–8am, Tue | — |
| 5. HOU → FLLHouston to Fort Lauderdale | Southwest Airlines | 64.8% | 65.0% | 0.37% | 8am–11am, Tue | — |
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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 2,923 flights.
- 5am–8am662 flights80.1%
- 8am–11am553 flights79.5%
- 11am–2pm432 flights79.4%
- 2pm–5pm760 flights77.6%
- 5pm–8pm496 flights76.1%
- 8pm–5am20 flights—
Scale runs 70% to 85%. Rows with fewer than 30 flights show a dash.
The early departures do better, though not dramatically: 80.1% on time for the 5am–8am window against 76.1% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 2pm–5pm window is the busiest, with 760 flights scheduled in it.
Explore
Filter IAH to FLL 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 IAH to FLL, the best departure window is 5am–8am at 80.1% on time and the worst is 5pm–8pm at 76.1%, a narrow gap of 4.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am80.1%
- 8–11am79.5%
- 11am–2pm79.4%
- 2–5pm77.6%
- 5–8pm76.1%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 25 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 64.4% on time, 25 points below September, the best at 89.3%. 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 296 flights.
Across the week, Tuesday is the strongest day at 86.4% on time and Sunday the weakest at 71.7%, a spread of 15 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 41,000 reported delay minutes.
- 34%Carrier
- 31%National Airspace System
- 31%Late-arriving aircraft
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 14,000 of the 41,000 delay minutes reported here. The split is drawn from 41,341 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 80.1% on time here.
Cancellations sit at 1.27% against a national 1.89%, which is ordinary. Diversions add another 0.10%.
Connections and stage length
What a delay here actually costs
8.3% 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 966 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 81.5% on time across 2,919 flights, 3 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 3 points of difference.
The sample behind these figures is 2,923 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 FLL after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 89.3% on time and July 64.4%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 2,883 completed flights over 12 months sit behind that.
Common questions
IAH to FLL questions
How often is IAH to FLL delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.5% of the 2,923 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on IAH to FLL?
United Airlines leads at 85.6% on time across 1,893 flights. Spirit Airlines is at the other end on 70.9%, a gap of 15 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 IAH to FLL?
The 5am–8am departure window is the strongest at 80.1% on time. The 5pm–8pm window is the weakest at 76.1%, 4 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 IAH to FLL?
July is the weakest month at 64.4% on time, compared with 89.3% in September. Across the year that is 25 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
- FLL to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- United Airlines on IAH to FLL85.6%
- Spirit Airlines on IAH to FLL70.9%
- Frontier Airlines on IAH to FLL61.6%
- JetBlue Airways on IAH to FLL43.9%
- IAH to ORD, a related route75.1%
- ATL to FLL, a related route70.7%
- IAH to DFW, a related route76.4%
- United Airlines on-time record85.6%
- Spirit Airlines on-time record70.9%
- Frontier Airlines on-time record61.6%
- Same route, different airline: where the carrier you pick matters most
- Worst months to fly in the US, ranked by the data
Direction matters. IAH to FLL and FLL to IAH 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.