Carrier route record

YXORD→STL

Republic Airways · Chicago to St. Louis

Flights: 444
Period: July 2025 to June 2026
Share of route: 14%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Republic Airways.

Republic on ORD to STL lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 444 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 727 at 75.0% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Republic on ORD to STL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

76.2%

Arrivals under 15 minutes late, of 433 completed flights

Avg delay

77 min

Across delayed arrivals only, not all flights

Cancelled

2.48%

National rate is 1.81%

Whole route

71.0%

Every carrier on ORD to STL, 3,068 flights

These figures cover 444 flights between July 2025 and June 2026. Beyond the headline rate, 9.2% 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

Republic against every carrier on ORD to STL

Republic flew 444 of the 3,068 flights on ORD to STL, about 14% of it. Its 76.2% on time is 5 points better than the route as a whole, which runs 71.0%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from Republic at 76.2% to American at 65.6%.

The choice of carrier is not cosmetic here. Envoy Air arrives on time 75.0% of the time; American Airlines manages 65.6%. Sample sizes sit next to every figure, because a two-point gap across 535 flights means less than a ten-point one.

On-time performance by carrier on ORD to STL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airways (this page)	444	76.2%	77 min	2.48%	B
Envoy Air	727	75.0%	52 min	2.34%	B
United Airlines	528	71.2%	79 min	1.33%	C
SkyWest Airlines	834	68.2%	73 min	4.20%	C−
American Airlines	535	65.6%	86 min	2.62%	C

SkyWest Airlines cancels 4.2% 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 Republic runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am45 flights78.6%
8am–11am8 flights—
11am–2pm146 flights83.2%
2pm–5pm189 flights73.7%
5pm–8pm17 flights—
8pm–5am39 flights62.2%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.2% on time, against 83.2% for the 11am–2pm 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 189 flights scheduled in it.

Across the year

Republic on ORD to STL through the year

Jul–Sep 202575 flights84.0%
Oct–Dec 2025226 flights71.4%
Jan–Mar 202666 flights82.5%
Apr–Jun 202677 flights77.3%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 76.2% on time across 444 flights.

Republic on ORD to STL did not run the same all year. Its best quarter was Jul–Sep 2025 at 84.0% on time and its weakest Oct–Dec 2025 at 71.4%, a swing of 13 points on roughly 111 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Saturday is the strongest day at 83.8% on time and Sunday the weakest at 64.3%. 20 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Republic runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 7,886 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.

Late-arriving aircraft
52%
National Airspace System
22%
Carrier
14%
Extreme weather
12%

Extreme weather accounts for 12% 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 1.9 times the usual weather exposure. The split is drawn from 7,886 reported delay minutes.

52% 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 7,886 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.

Cancellations sit at 2.48% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

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. 9.2% 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 11am–2pm window matters as much as it does.

The return leg is a different operation and performs like one: it runs 72.0% on time across 448 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 444 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 Republic on ORD to STL

Put together: treat all of this as provisional. 444 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 76.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 433 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures