Route reliability record
SDF→ORD
Louisville to Chicago
- Flights
- 2,795
- Period
- September 2025 to August 2026
- Distance
- 286 mi
- Carriers
- 5
This route lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,795 SDF to ORD flights, of which Republic Airways flew 1,853 at 82.8% on time.
Best time to fly SDF to ORD: a 5am–8am departure, ideally on a Thursday. Flights in that window arrived on time 86.8% of the time and Thursday flights 83.5%, against 79.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.3%
Arrivals under 15 minutes late, of 2,712 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
2.72%
National rate is 1.89%
Best carrier
Republic
82.8% on time across 1,853 flights
These figures cover 2,795 flights between September 2025 and August 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on SDF to ORD
The choice of carrier is not cosmetic here. Republic Airways arrives on time 82.8% of the time; SkyWest Airlines manages 69.6%. Sample sizes sit next to every figure, because a two-point gap across 650 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 1,853 | 82.8% | 68 min | 2.70% | B |
| Envoy Airthin sample | 283 | 79.6% | 82 min | 1.06% | B |
| SkyWest Airlines | 650 | 69.6% | 97 min | 3.38% | C− |
| American Airlinesthin sample | 3 | 66.7% | 48 min | 0.00% | C+ |
| United Airlinesthin sample | 5 | 40.0% | 54 min | 0.00% | F+ |
SkyWest Airlines cancels 3.4% 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
Flights on SDF to ORD
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Louisville to Chicago
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SDF → MDWLouisville to Chicago | Southwest Airlines | 82.7% | 84.1% | 1.64% | 5am–8am, Tue | — |
| 2. SDF → ORDLouisville to Chicago | Republic Airways | 80.6% | 82.8% | 2.70% | 5am–8am, Wed | YX 3422 07:00 |
| 3. SDF → ORDLouisville to Chicago | SkyWest Airlines | 67.2% | 69.6% | 3.38% | 5am–8am, Thu | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 13 points between the best and worst carrier.
- 5am–8am863 flights86.8%
- 8am–11am643 flights83.0%
- 11am–2pm359 flights81.5%
- 2pm–5pm363 flights70.7%
- 5pm–8pm564 flights67.2%
- 8pm–5am3 flights—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.8% of the time, against 67.2% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 863 flights scheduled in it.
Explore
Filter SDF to ORD by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SDF to ORD, the best departure window is 5am–8am at 86.8% on time and the worst is 5pm–8pm at 67.2%, a wide gap of 19.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.8%
- 8–11am83.0%
- 11am–2pm81.5%
- 2–5pm70.7%
- 5–8pm67.2%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 15 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
February is the weak month at 75.1% on time, against 89.6% 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 312 flights.
Across the week, Thursday is the strongest day at 83.5% on time and Friday the weakest at 74.7%, a spread of 9 points.
Delay causes
Why this route gets delayed
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 44,000 reported delay minutes.
- 42%National Airspace System
- 34%Late-arriving aircraft
- 19%Carrier
- 6%Extreme weather
42% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 18,000 minutes out of 44,000, against a national NAS share of 21%. The split is drawn from 44,482 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 86.8% on time here.
Cancellations run at 2.72%, against 1.89% nationally. That is roughly one flight in 40 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 actually costs
7.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
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 75.8% on time across 2,792 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.
The sample behind these figures is 2,795 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.
Work out the risk of missing a connection in ORD after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 89.6% on time and February 75.1%, a swing of 15 points. If the dates move at all, move them out of February before you think about anything else. 2,712 completed flights over 12 months sit behind that.
Common questions
SDF to ORD questions
How often is SDF to ORD delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.7% of the 2,795 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on SDF to ORD?
Republic Airways leads at 82.8% on time across 1,853 flights. SkyWest Airlines is at the other end on 69.6%, a gap of 13 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on SDF to ORD?
The 5am–8am departure window is the strongest at 86.8% on time. The 5pm–8pm window is the weakest at 67.2%, 20 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are February delays on SDF to ORD?
February is the weakest month at 75.1% on time, compared with 89.6% in September. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- ORD to SDF — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on SDF to ORD82.8%
- Envoy Air on SDF to ORD79.6%
- SkyWest Airlines on SDF to ORD69.6%
- SDF to ATL, a related route89.6%
- LGA to ORD, a related route66.7%
- SDF to DFW, a related route76.0%
- Republic Airways on-time record82.8%
- Envoy Air on-time record79.6%
- SkyWest Airlines on-time record69.6%
- The US routes with the most cancellations
- Same route, different airline: where the carrier you pick matters most
Direction matters. SDF to ORD and ORD to SDF are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.