Carrier route record
OOSTL→ORD
SkyWest Airlines · St. Louis to Chicago
- Flights
- 836
- Period
- July 2025 to June 2026
- Share of route
- 27%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with SkyWest Airlines.
SkyWest on STL to ORD carries a cancellation problem, not just a delay problem: 4.9% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, a little over half of flights arrive on time, worth a D− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 836 flights. The strongest carrier on the route with a full sample, American Airlines, flew 533 at 80.7% on time.
American Airlines is the most reliable of the four carriers covered here at 80.7% on time across 533 flights.
Key figures
On time
62.8%
Arrivals under 15 minutes late, of 794 completed flights
Avg delay
104 min
Across delayed arrivals only, not all flights
Cancelled
4.90%
National rate is 1.81%
Whole route
71.1%
Every carrier on STL to ORD, 3,070 flights
These figures cover 836 flights between July 2025 and June 2026. Beyond the headline rate, 18.4% 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
SkyWest against every carrier on STL to ORD
SkyWest flew 836 of the 3,070 flights on STL to ORD, about 27% of it. Its 62.8% on time is 8 points worse than the route as a whole, which runs 71.1%. Ranked by on-time rate it is last 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. American Airlines arrives on time 80.7% of the time; United Airlines manages 68.6%. Sample sizes sit next to every figure, because a two-point gap across 525 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 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 (this page) | 836 | 62.8% | 104 min | 4.90% | D− |
Republic Airways cancels 4.0% 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 SkyWest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1 flights—
- 8am–11am179 flights73.7%
- 11am–2pm168 flights63.4%
- 2pm–5pm222 flights61.7%
- 5pm–8pm118 flights66.4%
- 8pm–5am148 flights47.4%
Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 47.4% on time, against 73.7% 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 2pm–5pm window is the busiest, with 222 flights scheduled in it.
Across the year
SkyWest on STL to ORD through the year
December is the weak month at 46.4% on time, against 78.3% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 95 flights.
Across the week, Wednesday is the strongest day at 67.0% on time and Monday the weakest at 54.1%. 13 points is a smaller lever than departure hour, but it is free.
Delay causes
Why SkyWest 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 31,000 reported delay minutes.
- 38%Carrier
- 26%National Airspace System
- 23%Late-arriving aircraft
- 13%Extreme weather
- 0%Security
Extreme weather accounts for 13% 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 2.0 times the usual weather exposure. The split is drawn from 30,546 reported delay minutes.
The largest share of delay minutes, 38%, 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 12,000 of the 31,000 delay minutes reported here.
Cancellations run at 4.90%, against 1.81% nationally. That is about one flight in twenty 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. 18.4% 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 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 68.2% on time across 834 flights, 5 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 5 points of difference.
One caution: this is a thin sample. 836 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 SkyWest on STL to ORD
Put together: the delay figures matter less here than the 4.90% cancellation rate. A late arrival costs you close to two hours; 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. 794 completed flights over 12 months sit behind that.
Related
Where to go next
- STL to ORD, every carrier
- SkyWest on ORD to STL, the return leg
- American Airlines on STL to ORD80.7%
- Envoy Air on STL to ORD74.6%
- Republic Airways on STL to ORD72.0%
- United Airlines on STL to ORD68.6%
- SkyWest Airlines network-wide record
- St. Louis Lambert International (STL) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- The US routes with the most cancellations
- Same route, different airline: where the carrier you pick matters most
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.