Carrier route record
YXDTW→SDF
Republic Airways · Detroit to Louisville
- Flights
- 408
- Period
- July 2025 to June 2026
- Share of route
- 34%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Republic Airways.
Republic on DTW to SDF lands a B+, 2 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 an hour and a half on average. That is a workable record, not a spotless one. That rests on 408 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Republic on DTW 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
80.0%
Arrivals under 15 minutes late, of 404 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.81%
Whole route
77.2%
Every carrier on DTW to SDF, 1,190 flights
These figures cover 408 flights between July 2025 and June 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.
Carrier by carrier
Republic against every carrier on DTW to SDF
Republic flew 408 of the 1,190 flights on DTW to SDF, about 34% of it. Its 80.0% on time is 3 points better than the route as a whole, which runs 77.2%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Spirit at 83.3% to Delta at 45.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 18 | 83.3% | 39 min | 0.00% | B+ |
| Republic Airways (this page) | 408 | 80.0% | 94 min | 0.74% | B+ |
| SkyWest Airlines | 753 | 76.0% | 79 min | 1.46% | B |
| Delta Air Linesthin sample | 11 | 45.5% | 88 min | 0.00% | F+ |
Flight by flight
Republic flight numbers on DTW 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 19 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am4 flights—
- 11am–2pm—
- 2pm–5pm39 flights94.9%
- 5pm–8pm125 flights75.6%
- 8pm–5am240 flights79.8%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 2pm–5pm slot at 94.9% on time, ahead of 5pm–8pm at 75.6%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8pm–5am window is the busiest, with 240 flights scheduled in it.
Across the year
Republic on DTW to SDF through the year
September is the best month on the calendar at 100.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. October was the busiest month here, with 48 flights.
Across the week, Friday is the strongest day at 85.5% on time and Sunday the weakest at 69.0%. 17 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 45% of the 7,573 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.
- 45%Late-arriving aircraft
- 33%Carrier
- 12%Extreme weather
- 10%National Airspace System
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 7,573 reported delay minutes.
45% 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 7,573 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 are rare at 0.74%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
7.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
At 306 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 2pm–5pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 89.7% on time across 408 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 408 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 DTW to SDF
Put together: treat all of this as provisional. 408 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 80.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 404 completed flights over 12 months sit behind that.
Related
Where to go next
- DTW to SDF, every carrier
- Republic on SDF to DTW, the return leg
- SkyWest Airlines on DTW to SDF76.0%
- Republic Airways network-wide record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Why the first flight of the morning is statistically safest
- 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.