Carrier route record
AAIAH→MIA
American Airlines · Houston to Miami
- Flights
- 1,526
- Period
- July 2025 to June 2026
- Share of route
- 41%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on IAH to MIA lands a B, level with the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by close to two hours on average. That is a workable record, not a spotless one. That rests on 1,526 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,479 at 80.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate American on IAH to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.3%
Arrivals under 15 minutes late, of 1,501 completed flights
Avg delay
111 min
Across delayed arrivals only, not all flights
Cancelled
1.31%
National rate is 1.81%
Whole route
77.8%
Every carrier on IAH to MIA, 3,736 flights
These figures cover 1,526 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% 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
American against every carrier on IAH to MIA
American flew 1,526 of the 3,736 flights on IAH to MIA, about 41% of it. Its 78.3% on time is about level with the route as a whole at 77.8%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from United at 80.3% to Republic at 64.3%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 80.3% of the time; Spirit Airlines manages 70.7%. Sample sizes sit next to every figure, because a two-point gap across 441 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,479 | 80.3% | 61 min | 0.41% | B+ |
| Envoy Airthin sample | 122 | 78.5% | 52 min | 0.00% | B+ |
| American Airlines (this page) | 1,526 | 78.3% | 111 min | 1.31% | B |
| Spirit Airlines | 441 | 70.7% | 79 min | 3.17% | C− |
| Frontier Airlinesthin sample | 154 | 68.9% | 142 min | 1.95% | C |
| Republic Airwaysthin sample | 14 | 64.3% | 173 min | 0.00% | D+ |
Spirit Airlines cancels 3.2% 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
American flight numbers on IAH to MIA
Departure window
When American runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am726 flights89.0%
- 8am–11am149 flights77.7%
- 11am–2pm209 flights74.4%
- 2pm–5pm4 flights—
- 5pm–8pm438 flights63.1%
- 8pm–5am—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 63.1% on time, against 89.0% for the 5am–8am 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 5am–8am window is the busiest, with 726 flights scheduled in it.
Across the year
American on IAH to MIA through the year
August is the worst month at 67.2% on time, 20 points below September, the best at 87.0%. 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. March was the busiest month here, with 147 flights.
Across the week, Monday is the strongest day at 86.4% on time and Sunday the weakest at 65.4%. 21 points is a smaller lever than departure hour, but it is free.
Delay causes
Why American runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 36,000 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.
- 48%Late-arriving aircraft
- 34%Carrier
- 9%Extreme weather
- 9%National Airspace System
- 0%Security
48% 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 36,000 reported delay minutes here, that single category outweighs weather by 5 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 36,187 reported delay minutes.
The largest share of delay minutes, 34%, 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 12,000 of the 36,000 delay minutes reported here.
Cancellations sit at 1.31% against a national 1.81%, which is ordinary. Diversions add another 0.33%.
Connections and stage length
What a delay here costs
8.8% 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 last close to two hours, which a normal layover absorbs.
The 964 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 70.1% on time across 1,527 flights, 8 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 8 points of difference.
The sample behind these figures is 1,526 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 American on IAH to MIA
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.0% on time and August 67.2%, a swing of 20 points. If the dates move at all, move them out of August before you think about anything else. 1,501 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to MIA, every carrier
- American on MIA to IAH, the return leg
- United Airlines on IAH to MIA80.3%
- Envoy Air on IAH to MIA78.5%
- Spirit Airlines on IAH to MIA70.7%
- Frontier Airlines on IAH to MIA68.9%
- American Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Miami International (MIA) 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.