Route reliability record
FLL→IAH
Fort Lauderdale to Houston
- Flights
- 2,755
- Period
- July 2025 to June 2026
- Distance
- 966 mi
- Carriers
- 3
This route lands a B, 5 points better than the national rate of 77.6%. About one flight in six arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,755 flights, of which United Airlines flew 1,792 at 88.3% on time.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.6%. That gap is worth roughly 45 fewer late arrivals for every thousand flights.
Key figures
On time
82.1%
Arrivals under 15 minutes late, of 2,719 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
1.13%
National rate is 1.81%
Best carrier
United
88.3% on time across 1,792 flights
These figures cover 2,755 flights between July 2025 and June 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.
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 72.5%. Sample sizes sit next to every figure, because a two-point gap across 859 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,792 | 88.3% | 84 min | 0.78% | A+ |
| Spirit Airlines | 859 | 72.5% | 75 min | 1.75% | C |
| Frontier Airlinesthin sample | 104 | 52.0% | 75 min | 1.92% | F |
The spread between United and Spirit is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
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 25 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am559 flights94.4%
- 8am–11am334 flights92.7%
- 11am–2pm671 flights83.9%
- 2pm–5pm225 flights69.5%
- 5pm–8pm647 flights74.1%
- 8pm–5am319 flights70.2%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.4% of the time, against 69.5% for the afternoon window. That is 25 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 671 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 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.
October is the best month on the calendar at 89.9% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 294 flights.
Across the week, Tuesday is the strongest day at 89.0% on time and Sunday the weakest at 71.4%. 18 points is a smaller lever than departure hour, but it is free.
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 38,000 reported delay minutes.
- 37%Carrier
- 35%National Airspace System
- 26%Late-arriving aircraft
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 14,000 of the 38,000 delay minutes reported here. The split is drawn from 38,436 reported delay minutes.
35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 13,000 minutes out of 38,000, against a national NAS share of 21%.
Cancellations sit at 1.13% against a national 1.81%, which is ordinary. Diversions add another 0.18%.
Connections and stage length
What a delay here actually costs
7.2% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, 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. 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 79.8% on time across 2,760 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.
The sample behind these figures is 2,755 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.
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 March 72.3%, a swing of 18 points. If the dates move at all, move them out of March before you think about anything else. 2,719 completed flights over 12 months sit behind that.
Common questions
FLL to IAH questions
How often is FLL to IAH delayed?
About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.9% of the 2,755 flights in this analysis, against 22.4% 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 1,792 flights. Spirit Airlines is at the other end on 72.5%, a gap of 16 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 94.4% on time. The 2pm–5pm window is the weakest at 69.5%, 25 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 March delays on FLL to IAH?
March is the weakest month at 72.3% on time, compared with 89.9% in October. Across the year that is 18 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-time record88.3%
- Spirit Airlines on-time record72.5%
- Frontier Airlines on-time record52.0%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.