Carrier route record
AAMIA→ORD
American Airlines · Miami to Chicago
- Flights
- 3,015
- Period
- July 2025 to June 2026
- Share of route
- 68%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on MIA to ORD sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 3,015 flights, with a median arrival 4 minutes early.
The national on-time rate over the same period is 77.6%, so American on MIA to ORD runs 6 points behind the country as a whole. Across a thousand flights that is about 60 extra late arrivals.
Key figures
On time
71.6%
Arrivals under 15 minutes late, of 2,925 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
1.86%
National rate is 1.81%
Whole route
70.8%
Every carrier on MIA to ORD, 4,447 flights
These figures cover 3,015 flights between July 2025 and June 2026. Beyond the headline rate, 10.5% 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 MIA to ORD
American flew 3,015 of the 4,447 flights on MIA to ORD, most of the route. Its 71.6% on time is about level with the route as a whole at 70.8%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Frontier at 73.3% to Spirit at 63.2%. Two 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 46 | 73.3% | 175 min | 2.17% | C |
| American Airlines (this page) | 3,015 | 71.6% | 71 min | 1.86% | C |
| United Airlines | 1,040 | 70.7% | 85 min | 0.87% | C+ |
| Spirit Airlinesthin sample | 346 | 63.2% | 70 min | 6.07% | D− |
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 33 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–8am332 flights88.8%
- 8am–11am582 flights84.5%
- 11am–2pm223 flights79.6%
- 2pm–5pm566 flights65.4%
- 5pm–8pm585 flights55.5%
- 8pm–5am727 flights68.7%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 55.5% on time, against 88.8% 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 8pm–5am window is the busiest, with 727 flights scheduled in it.
Across the year
American on MIA to ORD through the year
July is the worst month at 55.5% on time, 25 points below November, the best at 80.1%. 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 288 flights.
Across the week, Tuesday is the strongest day at 78.5% on time and Sunday the weakest at 60.9%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why American 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 59,000 reported delay minutes.
- 34%Late-arriving aircraft
- 28%Carrier
- 28%National Airspace System
- 9%Extreme weather
- 0%Security
34% 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 59,000 reported delay minutes here, that single category outweighs weather by 4 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 58,862 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 88.8% on time here.
Cancellations sit at 1.86% against a national 1.81%, which is ordinary. Diversions add another 1.13%.
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. 10.5% 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 1,197 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 75.6% on time across 3,015 flights, 4 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 4 points of difference.
The sample behind these figures is 3,015 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 MIA to ORD
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 80.1% on time and July 55.5%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 2,925 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to ORD, every carrier
- American on ORD to MIA, the return leg
- United Airlines on MIA to ORD70.7%
- Spirit Airlines on MIA to ORD63.2%
- American Airlines network-wide record
- Miami International (MIA) delay statistics
- Chicago O'Hare International (ORD) 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.