Carrier route record
AAATL→ORD
American Airlines · Atlanta to Chicago
- Flights
- 688
- Period
- July 2025 to June 2026
- Share of route
- 11%
- Carriers
- 9
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on ATL 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, 5 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 688 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,611 at 74.3% on time.
United Airlines is the most reliable of the three carriers covered here at 74.3% on time across 1,611 flights.
Key figures
On time
72.2%
Arrivals under 15 minutes late, of 666 completed flights
Avg delay
98 min
Across delayed arrivals only, not all flights
Cancelled
3.05%
National rate is 1.81%
Whole route
70.6%
Every carrier on ATL to ORD, 6,406 flights
These figures cover 688 flights between July 2025 and June 2026. Beyond the headline rate, 11.9% 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 ATL to ORD
American flew 688 of the 6,406 flights on ATL to ORD, about 11% of it. Its 72.2% on time is 2 points better than the route as a whole, which runs 70.6%. Ranked by on-time rate it is number six of nine carriers on the route, where the range runs from PSA at 100.0% to Frontier at 62.8%. Five 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 74.3% of the time; Frontier Airlines manages 62.8%. Sample sizes sit next to every figure, because a two-point gap across 711 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| PSA Airlinesthin sample | 5 | 100.0% | — | 0.00% | A+ |
| SkyWest Airlinesthin sample | 40 | 84.2% | 88 min | 5.00% | B− |
| Spirit Airlinesthin sample | 75 | 83.8% | 38 min | 0.00% | B+ |
| United Airlines | 1,611 | 74.3% | 92 min | 1.55% | C |
| Republic Airwaysthin sample | 287 | 72.4% | 65 min | 5.92% | C− |
| American Airlines (this page) | 688 | 72.2% | 98 min | 3.05% | C− |
| Envoy Airthin sample | 364 | 71.3% | 83 min | 2.20% | C |
| Delta Air Lines | 2,625 | 69.1% | 63 min | 2.21% | C |
| Frontier Airlines | 711 | 62.8% | 111 min | 2.67% | D |
United leads Frontier by 12 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am221 flights89.3%
- 8am–11am34 flights71.9%
- 11am–2pm146 flights82.3%
- 2pm–5pm110 flights64.2%
- 5pm–8pm128 flights47.5%
- 8pm–5am49 flights47.9%
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.5% on time, against 89.3% 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 221 flights scheduled in it.
Across the year
American on ATL to ORD through the year
September is the best month on the calendar at 85.1% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 111 flights.
Across the week, Friday is the strongest day at 81.0% on time and Monday the weakest at 63.8%. 17 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 18,000 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
- 18%Carrier
- 18%National Airspace System
- 15%Extreme weather
- 0%Security
Extreme weather accounts for 15% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.4 times the usual weather exposure. The split is drawn from 18,140 reported delay minutes.
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 18,000 reported delay minutes here, that single category outweighs weather by 3 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.
Cancellations run at 3.05%, 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. 11.9% 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 606 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 65.3% on time across 689 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 688 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 ATL to ORD
Put together: the delay figures matter less here than the 3.05% cancellation rate. A late arrival costs you an hour and a half; 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. 666 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to ORD, every carrier
- American on ORD to ATL, the return leg
- United Airlines on ATL to ORD74.3%
- Republic Airways on ATL to ORD72.4%
- Envoy Air on ATL to ORD71.3%
- Delta Air Lines on ATL to ORD69.1%
- Frontier Airlines on ATL to ORD62.8%
- American Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) 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.