Route reliability record
FLL→IAH
Fort Lauderdale to Houston
- Flights
- 2,919
- Period
- September 2025 to August 2026
- Distance
- 966 mi
- Carriers
- 4
This route lands a B, 4 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,919 FLL to IAH flights, of which United Airlines flew 1,894 at 88.3% on time.
Best time to fly FLL to IAH: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.8% of the time and Wednesday flights 88.2%, against 81.5% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.3%. That gap is worth roughly 42 fewer late arrivals for every thousand flights.
Key figures
On time
81.5%
Arrivals under 15 minutes late, of 2,874 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.30%
National rate is 1.89%
Best carrier
United
88.3% on time across 1,894 flights
These figures cover 2,919 flights between September 2025 and August 2026. The median arrival is 13 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on FLL to IAH
The choice of carrier is not cosmetic here. United Airlines arrives on time 88.3% of the time; Spirit Airlines manages 71.7%. Sample sizes sit next to every figure, because a two-point gap across 698 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,894 | 88.3% | 78 min | 0.63% | A+ |
| Spirit Airlines | 698 | 71.7% | 70 min | 2.15% | C |
| JetBlue Airwaysthin sample | 162 | 70.1% | 71 min | 4.32% | C− |
| Frontier Airlinesthin sample | 165 | 53.8% | 83 min | 2.42% | F |
The spread between United and Spirit is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.
Flight by flight
Flights on FLL to IAH
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 Houston
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. FLL → IAHFort Lauderdale to Houston | United Airlines | 87.7% | 88.3% | 0.63% | 5am–8am, Thu | UA 2314 06:15 |
| 2. MIA → IAHMiami to Houston | United Airlines | 87.1% | 87.5% | 0.49% | 5am–8am, Wed | UA 1216 16:53 |
| 3. MIA → IAHMiami to Houston | American Airlines | 70.7% | 71.5% | 1.15% | 5am–8am, Tue | AA 2230 21:50 |
| 4. FLL → IAHFort Lauderdale to Houston | Spirit Airlines | 70.2% | 71.7% | 2.15% | 5am–8am, Tue | — |
| 5. FLL → HOUFort Lauderdale to Houston | Southwest Airlines | 69.5% | 70.2% | 0.99% | 5am–8am, Wed | — |
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 26 points, against 17 points between the best and worst carrier.
- 5am–8am507 flights93.8%
- 8am–11am408 flights90.3%
- 11am–2pm787 flights82.0%
- 2pm–5pm225 flights71.3%
- 5pm–8pm650 flights76.4%
- 8pm–5am342 flights67.6%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.8% of the time, against 67.6% for the overnight window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 787 flights scheduled in it.
Explore
Filter FLL to IAH 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 IAH, the best departure window is 5am–8am at 93.8% on time and the worst is 8pm–5am at 67.6%, a wide gap of 26.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.8%
- 8–11am90.3%
- 11am–2pm82.0%
- 2–5pm71.3%
- 5–8pm76.4%
- 8pm–5am67.6%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
This route's year swings by 19 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 71.2% on time, 19 points below October, the best at 89.9%. 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 297 flights.
Across the week, Wednesday is the strongest day at 88.2% on time and Sunday the weakest at 72.7%, a spread of 16 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 40,000 reported delay minutes.
- 36%Carrier
- 32%Late-arriving aircraft
- 30%National Airspace System
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 14,000 of the 40,000 delay minutes reported here. The split is drawn from 40,036 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 93.8% on time here.
Cancellations sit at 1.30% against a national 1.89%, which is ordinary. Diversions add another 0.24%.
Connections and stage length
What a delay here actually costs
7.3% 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 a little over 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 78.5% on time across 2,923 flights, 3 points below 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 2,919 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 IAH 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. October runs 89.9% on time and July 71.2%, a swing of 19 points. If the dates move at all, move them out of July before you think about anything else. 2,874 completed flights over 12 months sit behind that.
Common questions
FLL to IAH questions
How often is FLL to IAH delayed?
Roughly 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 18.5% of the 2,919 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 IAH?
United Airlines leads at 88.3% on time across 1,894 flights. Spirit Airlines is at the other end on 71.7%, a gap of 17 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 IAH?
The 5am–8am departure window is the strongest at 93.8% on time. The 8pm–5am window is the weakest at 67.6%, 26 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 IAH?
July is the weakest month at 71.2% on time, compared with 89.9% in October. Across the year that is 19 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
- IAH to FLL — the return legseparate record
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on FLL to IAH88.3%
- Spirit Airlines on FLL to IAH71.7%
- JetBlue Airways on FLL to IAH70.1%
- Frontier Airlines on FLL to IAH53.8%
- FLL to ATL, a related route71.0%
- ORD to IAH, a related route76.0%
- FLL to LGA, a related route64.8%
- United Airlines on-time record88.3%
- Spirit Airlines on-time record71.7%
- JetBlue Airways on-time record70.1%
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.05 million flight records
Direction matters. FLL to IAH and IAH 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.