Carrier route record
F9FLL→IAH
Frontier Airlines · Fort Lauderdale to Houston
- Flights
- 104
- Period
- July 2025 to June 2026
- Share of route
- 4%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on FLL to IAH earns an F, which is as low as this site's scale goes for a reason. Only 52.0% of flights arrive inside the 15-minute window, 26 points worse than the national rate of 77.6%. Late arrivals average a little over an hour. Treat any tight connection here as a coin flip. That rests on 104 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,792 at 88.3% on time.
The national on-time rate over the same period is 77.6%, so Frontier on FLL to IAH runs 26 points behind the country as a whole. Across a thousand flights that is about 256 extra late arrivals.
Key figures
On time
52.0%
Arrivals under 15 minutes late, of 102 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.92%
National rate is 1.81%
Whole route
82.1%
Every carrier on FLL to IAH, 2,755 flights
These figures cover 104 flights between July 2025 and June 2026. Beyond the headline rate, 16.7% 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
Frontier against every carrier on FLL to IAH
Frontier flew 104 of the 2,755 flights on FLL to IAH, about 4% of it. Its 52.0% on time is 30 points worse than the route as a whole, which runs 82.1%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 88.3% to Frontier at 52.0%.
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 Airlines (this page)thin 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
When Frontier runs best on this route
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 104 flights.
There are not enough flights in each departure window to split Frontier's FLL to IAH record by time of day without the percentages moving on noise. The headline rate of 52.0% is the reliable figure here.
Across the year
Frontier on FLL to IAH through the year
- Oct–Dec 20256 flights—
- Jan–Mar 202637 flights68.6%
- Apr–Jun 202661 flights41.0%
Scale runs 35% to 75%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 52.0% on time across 104 flights.
Split by quarter, Frontier on FLL to IAH logged 6 flights in Oct–Dec 2025, 37 flights in Jan–Mar 2026 and 61 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 52.0% annual figure is the one to use.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 3,655 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 43%Late-arriving aircraft
- 36%Carrier
- 21%National Airspace System
- 0%Extreme weather
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 3,655 reported delay minutes here, that single category outweighs weather by 43 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 3,655 reported delay minutes.
The largest share of delay minutes, 36%, 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 1,308 of the 3,655 delay minutes reported here.
Cancellations sit at 1.92% 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. 16.7% 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 is a different operation and performs like one: it runs 59.0% on time across 104 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 104 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 Frontier on FLL to IAH
Put together: treat all of this as provisional. 104 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 52.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 102 completed flights over 12 months sit behind that.
Related
Where to go next
- FLL to IAH, every carrier
- Frontier on IAH to FLL, the return leg
- United Airlines on FLL to IAH88.3%
- Spirit Airlines on FLL to IAH72.5%
- Frontier Airlines network-wide record
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.