Carrier route record
F9IAH→ATL
Frontier Airlines · Houston to Atlanta
- 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 IAH to ATL draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 767 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,257 at 81.9% on time.
United Airlines is the most reliable of the three carriers covered here at 81.9% on time across 1,257 flights.
Key figures
On time
61.7%
Arrivals under 15 minutes late, of 750 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
2.22%
National rate is 1.81%
Whole route
77.5%
Every carrier on IAH to ATL, 4,906 flights
These figures cover 767 flights between July 2025 and June 2026. Beyond the headline rate, 13.3% 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 IAH to ATL
Frontier flew 767 of the 4,906 flights on IAH to ATL, about 16% of it. Its 61.7% on time is 16 points worse than the route as a whole, which runs 77.5%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from United at 81.9% to Frontier at 61.7%.
The three carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,257 | 81.9% | 69 min | 0.72% | B+ |
| Delta Air Lines | 2,507 | 80.2% | 66 min | 2.07% | B |
| Spirit Airlines | 375 | 77.4% | 58 min | 4.27% | B− |
| Frontier Airlines (this page) | 767 | 61.7% | 68 min | 2.22% | D |
Spirit Airlines cancels 4.3% 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 IAH to ATL
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 39 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am310 flights63.6%
- 8am–11am67 flights85.1%
- 11am–2pm69 flights65.7%
- 2pm–5pm53 flights46.2%
- 5pm–8pm209 flights55.4%
- 8pm–5am59 flights56.9%
Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 85.1% of the time, against 46.2% for the afternoon window. That is 39 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 310 flights scheduled in it.
Across the year
Frontier on IAH to ATL through the year
September is the best month on the calendar at 80.4% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. June was the busiest month here, with 89 flights.
Across the week, Wednesday is the strongest day at 69.7% on time and Sunday the weakest at 52.1%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier 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 19,000 reported delay minutes.
- 40%Late-arriving aircraft
- 30%Carrier
- 28%National Airspace System
- 2%Extreme weather
40% 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 24 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 19,407 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 85.1% on time here.
Cancellations sit at 2.22% 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. 13.3% 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 68.9% on time across 767 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. 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 IAH to ATL
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 61.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 750 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to ATL, every carrier
- Frontier on ATL to IAH, the return leg
- United Airlines on IAH to ATL81.9%
- Delta Air Lines on IAH to ATL80.2%
- Spirit Airlines on IAH to ATL77.4%
- Frontier Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Why the first flight of the morning is statistically safest
- 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.