Carrier route record
F9ATL→IAH
Frontier Airlines · Atlanta to Houston
- Flights
- 767
- Period
- July 2025 to June 2026
- Share of route
- 16%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on ATL to IAH sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 767 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,255 at 85.1% on time.
United Airlines is the most reliable of the three carriers covered here at 85.1% on time across 1,255 flights.
Key figures
On time
68.9%
Arrivals under 15 minutes late, of 756 completed flights
Avg delay
82 min
Across delayed arrivals only, not all flights
Cancelled
1.43%
National rate is 1.81%
Whole route
76.4%
Every carrier on ATL to IAH, 4,914 flights
These figures cover 767 flights between July 2025 and June 2026. Beyond the headline rate, 14.6% 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 ATL to IAH
Frontier flew 767 of the 4,914 flights on ATL to IAH, about 16% of it. Its 68.9% on time is 8 points worse than the route as a whole, which runs 76.4%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 85.1% to Spirit at 66.3%.
The choice of carrier is not cosmetic here. United Airlines arrives on time 85.1% of the time; Spirit Airlines manages 66.3%. Sample sizes sit next to every figure, because a two-point gap across 384 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,255 | 85.1% | 78 min | 1.12% | A |
| Delta Air Lines | 2,508 | 75.9% | 55 min | 1.95% | B |
| Frontier Airlines (this page) | 767 | 68.9% | 82 min | 1.43% | C |
| Spirit Airlines | 384 | 66.3% | 76 min | 4.69% | C− |
Spirit Airlines cancels 4.7% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Frontier flight numbers on ATL to IAH
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 19 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am73 flights80.8%
- 8am–11am63 flights77.0%
- 11am–2pm18 flights—
- 2pm–5pm254 flights69.8%
- 5pm–8pm39 flights84.2%
- 8pm–5am320 flights62.7%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 62.7% on time, against 84.2% for the 5pm–8pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 320 flights scheduled in it.
Across the year
Frontier on ATL to IAH through the year
July is the worst month at 43.5% on time, 40 points below February, the best at 83.3%. 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. June was the busiest month here, with 89 flights.
Across the week, Thursday is the strongest day at 78.8% on time and Monday the weakest at 61.2%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 19,000 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.
- 46%Late-arriving aircraft
- 39%Carrier
- 15%National Airspace System
- 1%Extreme weather
46% 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 19,000 reported delay minutes here, that single category outweighs weather by 46 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 19,336 reported delay minutes.
The largest share of delay minutes, 39%, 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 7,497 of the 19,000 delay minutes reported here.
Cancellations sit at 1.43% 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. 14.6% 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 689 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 61.7% on time across 767 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 767 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 ATL to IAH
Put together: treat all of this as provisional. 767 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 68.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 756 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to IAH, every carrier
- Frontier on IAH to ATL, the return leg
- United Airlines on ATL to IAH85.1%
- Delta Air Lines on ATL to IAH75.9%
- Spirit Airlines on ATL to IAH66.3%
- Frontier Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
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.