Carrier route record
AASTL→ORD
American Airlines · St. Louis to Chicago
- Flights
- 533
- Period
- July 2025 to June 2026
- Share of route
- 17%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on STL to ORD lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 2.1 hours on average. That is a workable record, not a spotless one. That rests on 533 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 728 at 74.6% on time.
The US average over the same twelve months is 77.6%, so there is little to separate American on STL to ORD from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.7%
Arrivals under 15 minutes late, of 519 completed flights
Avg delay
126 min
Across delayed arrivals only, not all flights
Cancelled
2.44%
National rate is 1.81%
Whole route
71.1%
Every carrier on STL to ORD, 3,070 flights
These figures cover 533 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% 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 STL to ORD
American flew 533 of the 3,070 flights on STL to ORD, about 17% of it. Its 80.7% on time is 10 points better than the route as a whole, which runs 71.1%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from American at 80.7% to SkyWest at 62.8%.
The choice of carrier is not cosmetic here. Envoy Air arrives on time 74.6% of the time; SkyWest Airlines manages 62.8%. Sample sizes sit next to every figure, because a two-point gap across 836 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines (this page) | 533 | 80.7% | 126 min | 2.44% | B |
| Envoy Air | 728 | 74.6% | 93 min | 2.61% | C |
| Republic Airways | 448 | 72.0% | 76 min | 4.02% | C− |
| United Airlines | 525 | 68.6% | 85 min | 1.52% | C |
| SkyWest Airlines | 836 | 62.8% | 104 min | 4.90% | D− |
SkyWest Airlines cancels 4.9% 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.
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 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am430 flights84.4%
- 8am–11am4 flights—
- 11am–2pm44 flights59.5%
- 2pm–5pm4 flights—
- 5pm–8pm48 flights66.7%
- 8pm–5am3 flights—
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 59.5% on time against 84.4% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5am–8am window is the busiest, with 430 flights scheduled in it.
Across the year
American on STL to ORD through the year
October is the best month on the calendar at 88.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. April was the busiest month here, with 102 flights.
Across the week, Wednesday is the strongest day at 88.8% on time and Monday the weakest at 74.6%. 14 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. Carrier accounts for 52% of the 13,000 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.
- 52%Carrier
- 27%Late-arriving aircraft
- 18%National Airspace System
- 4%Extreme weather
The largest share of delay minutes, 52%, 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 6,526 of the 13,000 delay minutes reported here. The split is drawn from 12,601 reported delay minutes.
Cancellations sit at 2.44% against a national 1.81%, which is ordinary. Diversions add another 0.19%.
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. 9.1% 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.
At 258 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 65.6% on time across 535 flights, 15 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 15 points of difference.
One caution: this is a thin sample. 533 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 STL to ORD
Put together: treat all of this as provisional. 533 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 80.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 519 completed flights over 12 months sit behind that.
Related
Where to go next
- STL to ORD, every carrier
- American on ORD to STL, the return leg
- Envoy Air on STL to ORD74.6%
- Republic Airways on STL to ORD72.0%
- United Airlines on STL to ORD68.6%
- SkyWest Airlines on STL to ORD62.8%
- American Airlines network-wide record
- St. Louis Lambert International (STL) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Same route, different airline: where the carrier you pick matters most
- 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.