Carrier route record
AAIAH→ORD
American Airlines · Houston to Chicago
- 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 IAH to ORD carries a cancellation problem, not just a delay problem: 3.5% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, about two flights in three arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 798 flights, with a median arrival 3 minutes early.
The national on-time rate over the same period is 77.6%, so American on IAH to ORD runs 11 points behind the country as a whole. Across a thousand flights that is about 105 extra late arrivals.
Key figures
On time
67.1%
Arrivals under 15 minutes late, of 768 completed flights
Avg delay
122 min
Across delayed arrivals only, not all flights
Cancelled
3.51%
National rate is 1.81%
Whole route
74.8%
Every carrier on IAH to ORD, 6,080 flights
These figures cover 798 flights between July 2025 and June 2026. Beyond the headline rate, 15.6% 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
American against every carrier on IAH to ORD
American flew 798 of the 6,080 flights on IAH to ORD, about 13% of it. Its 67.1% on time is 8 points worse than the route as a whole, which runs 74.8%. Ranked by on-time rate it is number four of eight carriers on the route, where the range runs from United at 78.2% to PSA at 50.0%. 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 | 4,007 | 78.2% | 70 min | 0.60% | B+ |
| Envoy Airthin sample | 359 | 72.8% | 62 min | 1.11% | C |
| Republic Airwaysthin sample | 357 | 71.7% | 80 min | 3.64% | C− |
| American Airlines (this page) | 798 | 67.1% | 122 min | 3.51% | C− |
| Spirit Airlinesthin sample | 305 | 66.0% | 70 min | 4.59% | C− |
| Frontier Airlinesthin sample | 248 | 61.8% | 130 min | 2.82% | D |
| SkyWest Airlinesthin sample | 2 | 50.0% | 38 min | 0.00% | F+ |
| PSA Airlinesthin sample | 4 | 50.0% | 156 min | 0.00% | F+ |
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 42 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–8am324 flights80.8%
- 8am–11am84 flights76.8%
- 11am–2pm188 flights69.5%
- 2pm–5pm3 flights—
- 5pm–8pm199 flights38.6%
- 8pm–5am—
Scale runs 30% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 38.6% on time, against 80.8% 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 324 flights scheduled in it.
Across the year
American on IAH to ORD through the year
April is the best month on the calendar at 86.5% 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 80.5% on time and Sunday the weakest at 55.2%. 25 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 54% of the 31,000 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.
- 54%Late-arriving aircraft
- 28%Carrier
- 14%National Airspace System
- 3%Extreme weather
- 0%Security
54% 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 31,000 reported delay minutes here, that single category outweighs weather by 20 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 30,748 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 80.8% on time here.
Cancellations run at 3.51%, against 1.81% nationally. That is about 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. 15.6% 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 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 60.6% on time across 798 flights, 6 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 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 IAH to ORD
Put together: the delay figures matter less here than the 3.51% cancellation rate. A late arrival costs you close to two hours; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 768 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to ORD, every carrier
- American on ORD to IAH, the return leg
- United Airlines on IAH to ORD78.2%
- Envoy Air on IAH to ORD72.8%
- Republic Airways on IAH to ORD71.7%
- Spirit Airlines on IAH to ORD66.0%
- Frontier Airlines on IAH to ORD61.8%
- American Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Chicago O'Hare International (ORD) 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.