Carrier route record
NKIAH→FLL
Spirit Airlines · Houston to Fort Lauderdale
- Flights
- 864
- Period
- July 2025 to June 2026
- Share of route
- 31%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Spirit Airlines.
Spirit on IAH 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, 6 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 864 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so Spirit on IAH to FLL runs 6 points behind the country as a whole. Across a thousand flights that is about 60 extra late arrivals.
Key figures
On time
71.6%
Arrivals under 15 minutes late, of 848 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.85%
National rate is 1.81%
Whole route
79.8%
Every carrier on IAH to FLL, 2,760 flights
These figures cover 864 flights between July 2025 and June 2026. Beyond the headline rate, 12.7% 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
Spirit against every carrier on IAH to FLL
Spirit flew 864 of the 2,760 flights on IAH to FLL, about 31% of it. Its 71.6% on time is 8 points worse than the route as a whole, which runs 79.8%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from United at 85.0% to Frontier at 59.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,792 | 85.0% | 64 min | 0.73% | A+ |
| Spirit Airlines (this page) | 864 | 71.6% | 73 min | 1.85% | C |
| Frontier Airlinesthin sample | 104 | 59.0% | 48 min | 3.85% | D− |
Departure window
When Spirit runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am392 flights77.5%
- 8am–11am40 flights71.8%
- 11am–2pm97 flights76.0%
- 2pm–5pm133 flights58.5%
- 5pm–8pm175 flights65.5%
- 8pm–5am27 flights—
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 77.5% of the time, against 58.5% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 392 flights scheduled in it.
Across the year
Spirit on IAH to FLL through the year
October is the best month on the calendar at 88.5% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. December was the busiest month here, with 95 flights.
Across the week, Tuesday is the strongest day at 82.2% on time and Sunday the weakest at 57.6%. 25 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Spirit 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 18,000 reported delay minutes.
- 38%Carrier
- 35%National Airspace System
- 22%Late-arriving aircraft
- 4%Extreme weather
- 1%Security
The largest share of delay minutes, 38%, 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 6,646 of the 18,000 delay minutes reported here. The split is drawn from 17,516 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 6,197 minutes out of 18,000, against a national NAS share of 21%.
Cancellations sit at 1.85% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
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. 12.7% 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 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 72.5% on time across 859 flights, within about a point 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. 864 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 Spirit on IAH to FLL
Put together: treat all of this as provisional. 864 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 71.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 848 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to FLL, every carrier
- Spirit on FLL to IAH, the return leg
- United Airlines on IAH to FLL85.0%
- Frontier Airlines on IAH to FLL59.0%
- Spirit Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.04 million flight records
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.