Carrier route record
YXORD→SDF
Republic Airways · Chicago to Louisville
- Flights
- 1,733
- Period
- July 2025 to June 2026
- Share of route
- 62%
- 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 SDF carries a cancellation problem, not just a delay problem: 3.9% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,733 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 415 at 84.1% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Republic on ORD to SDF from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 1,662 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
3.87%
National rate is 1.81%
Whole route
75.3%
Every carrier on ORD to SDF, 2,804 flights
These figures cover 1,733 flights between July 2025 and June 2026. Beyond the headline rate, 10.1% 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
Republic against every carrier on ORD to SDF
Republic flew 1,733 of the 2,804 flights on ORD to SDF, most of the route. Its 75.0% on time is about level with the route as a whole at 75.3%. Ranked by on-time rate it is number two of five carriers on the route, where the range runs from Envoy at 84.1% to United at 33.3%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Envoy Air arrives on time 84.1% of the time; SkyWest Airlines manages 71.0%. Sample sizes sit next to every figure, because a two-point gap across 645 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Air | 415 | 84.1% | 54 min | 1.20% | B |
| Republic Airways (this page) | 1,733 | 75.0% | 75 min | 3.87% | B− |
| SkyWest Airlines | 645 | 71.0% | 69 min | 3.10% | C− |
| American Airlinesthin sample | 4 | 50.0% | 71 min | 0.00% | F+ |
| United Airlinesthin sample | 6 | 33.3% | 45 min | 0.00% | F+ |
SkyWest Airlines cancels 3.1% 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.
Flight by flight
Republic flight numbers on ORD to SDF
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 25 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am54 flights96.3%
- 8am–11am163 flights82.0%
- 11am–2pm23 flights—
- 2pm–5pm257 flights75.4%
- 5pm–8pm698 flights74.3%
- 8pm–5am538 flights71.8%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 96.3% of the time, against 71.8% for the overnight window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 698 flights scheduled in it.
Across the year
Republic on ORD to SDF through the year
July is the worst month at 57.5% on time, 32 points below September, the best at 89.2%. 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. May was the busiest month here, with 204 flights.
Across the week, Thursday is the strongest day at 78.7% on time and Sunday the weakest at 70.0%. 9 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 56% of the 31,000 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.
- 56%Late-arriving aircraft
- 20%Carrier
- 17%National Airspace System
- 7%Extreme weather
56% 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 31,000 reported delay minutes here, that single category outweighs weather by 8 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 31,339 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 96.3% on time here.
Cancellations run at 3.87%, against 1.81% nationally. That is about one flight in 25 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. 10.1% 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 286 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 82.5% on time across 1,736 flights, 8 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 8 points of difference.
The sample behind these figures is 1,733 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 Republic on ORD to SDF
Put together: the delay figures matter less here than the 3.87% cancellation rate. A late arrival costs you a little over an hour; 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. 1,662 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to SDF, every carrier
- Republic on SDF to ORD, the return leg
- Envoy Air on ORD to SDF84.1%
- SkyWest Airlines on ORD to SDF71.0%
- Republic Airways network-wide record
- 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.