Carrier route record
AAORD→IAH
American Airlines · Chicago to Houston
- Flights
- 798
- Period
- July 2025 to June 2026
- Share of route
- 13%
- Carriers
- 8
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on ORD to IAH draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 798 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.6%, so American on ORD to IAH runs 17 points behind the country as a whole. Across a thousand flights that is about 170 extra late arrivals.
Key figures
On time
60.6%
Arrivals under 15 minutes late, of 771 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
3.01%
National rate is 1.81%
Whole route
75.0%
Every carrier on ORD to IAH, 6,077 flights
These figures cover 798 flights between July 2025 and June 2026. Beyond the headline rate, 18.2% 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 ORD to IAH
American flew 798 of the 6,077 flights on ORD to IAH, about 13% of it. Its 60.6% on time is 14 points worse than the route as a whole, which runs 75.0%. Ranked by on-time rate it is number six of eight carriers on the route, where the range runs from United at 78.6% to SkyWest at 0.0%. Six 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 | 4,000 | 78.6% | 67 min | 0.65% | B+ |
| Republic Airwaysthin sample | 359 | 76.3% | 69 min | 2.51% | B |
| Frontier Airlinesthin sample | 249 | 76.0% | 96 min | 2.41% | B |
| Envoy Airthin sample | 358 | 74.4% | 63 min | 1.40% | C |
| Spirit Airlinesthin sample | 307 | 63.1% | 102 min | 5.54% | D− |
| American Airlines (this page) | 798 | 60.6% | 84 min | 3.01% | D− |
| PSA Airlinesthin sample | 4 | 50.0% | 74 min | 0.00% | F+ |
| SkyWest Airlinesthin sample | 2 | 0.0% | 32 min | 0.00% | F+ |
Flight by flight
American flight numbers on ORD to IAH
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 25 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–8am149 flights73.5%
- 8am–11am120 flights75.6%
- 11am–2pm17 flights—
- 2pm–5pm188 flights54.4%
- 5pm–8pm25 flights—
- 8pm–5am299 flights50.7%
Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 50.7% on time, against 75.6% for the 8am–11am 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 299 flights scheduled in it.
Across the year
American on ORD to IAH through the year
September is the best month on the calendar at 73.6% 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 120 flights.
Across the week, Tuesday is the strongest day at 77.9% on time and Sunday the weakest at 50.0%. 28 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 46% of the 26,000 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
- 35%Carrier
- 15%National Airspace System
- 4%Extreme weather
- 0%Security
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 26,000 reported delay minutes here, that single category outweighs weather by 11 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 25,656 reported delay minutes.
The largest share of delay minutes, 35%, 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 8,931 of the 26,000 delay minutes reported here.
Cancellations run at 3.01%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
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. 18.2% 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 925 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 67.1% on time across 798 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 798 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 American on ORD to IAH
Put together: the delay figures matter less here than the 3.01% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 771 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to IAH, every carrier
- American on IAH to ORD, the return leg
- United Airlines on ORD to IAH78.6%
- Republic Airways on ORD to IAH76.3%
- Frontier Airlines on ORD to IAH76.0%
- Envoy Air on ORD to IAH74.4%
- Spirit Airlines on ORD to IAH63.1%
- American Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- The US routes with the most cancellations
- 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.