Flight number record
YX 3598
Republic Airways · Chicago to Louisville
- Route
- ORD → SDF
- Departs
- 17:50
- Flights
- 348
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s YX 3598, check with Republic Airways. Republic Airways flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
YX 3598 sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 348 flights, with a median arrival 5 minutes early.
Key figures
On time
74.2%
Arrivals under 15 minutes late, of 333 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
4.31%
National rate is 1.89%
1 hour+ late
9.0%
National rate is 8.3%
These figures cover 348 flights between September 2025 and August 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When YX 3598 flies
YX 3598 flies ORD to SDF without a single fixed slot. Its most common scheduled departure was 17:50, used on 143 of 348 flights, with 17:45 (74 flights) and 18:10 (35 flights) next.
- Departs 17:50143 flights41.1%
- Departs 17:4574 flights21.3%
- Departs 18:1035 flights10.1%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and YX 3598 runs 6 points better at 74.2%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
YX 3598 next to ORD to SDF
Every carrier on ORD to SDF combined arrived on time 75.8% of the time across 2,792 flights, so YX 3598 is 2 points behind it. Republic flew 1,850 flights on the same city pair under all its flight numbers, including this one, and those ran 75.8% on time. Across its whole network Republic Airways managed 78.1%, which this flight trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| YX 3598thin sample | 348 | 74.2% | 80 min | 4.31% | C− |
| All Republic Airways on ORD–SDF | 1,850 | 75.8% | 77 min | 4.11% | B− |
| All carriers on ORD–SDF | 2,792 | 75.8% | 71 min | 3.58% | B− |
| Republic Airways, whole network | 364,452 | 78.1% | 74 min | 4.55% | B− |
Across the year
YX 3598 quarter by quarter
YX 3598 did not run the same all year. Its best quarter was Jul–Sep 2025 at 90.0% on time and its weakest Jul–Sep 2026 at 67.8%, a swing of 22 points on roughly 70 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.
- Jul–Sep 202530 flights90.0%
- Oct–Dec 202575 flights74.6%
- Jan–Mar 202690 flights72.1%
- Apr–Jun 202691 flights74.7%
- Jul–Sep 202662 flights67.8%
Scale runs 60% to 95%.
By weekday, YX 3598 did best on Thursday at 84.8% on time and worst on Sunday at 66.7%. Each day rests on about 50 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late YX 3598 runs when it is late
YX 3598 often beats the schedule: 100 of 333 completed flights, 30%, arrived 15 minutes or more early. The 86 late arrivals split 27 under half an hour, 29 between 30 and 60 minutes, and 30 an hour or more.
- 15+ min early100 flights30.0%
- Within 15 min147 flights44.1%
- 15–29 min late27 flights8.1%
- 30–59 min late29 flights8.7%
- 1–2 hours late16 flights4.8%
- 2+ hours late14 flights4.2%
Scale runs 0% to 100%.
Share of 333 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 71 departures that left 15 minutes late or more, only 6 made it up before arrival. In the other direction, 21 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SDF.
The worst days
Worst days for YX 3598
The latest arrival of the period was on 4 July 2026, 13 hours 47 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 July 2026 | 13 hours 47 minutes | Carrier |
| 14 June 2026 | 12 hours 9 minutes | Carrier |
| 18 March 2026 | 4 hours 52 minutes | Late-arriving aircraft |
| 31 August 2026 | 4 hours 5 minutes | Late-arriving aircraft |
| 11 August 2026 | 3 hours 45 minutes | Carrier |
Delay causes
Why YX 3598 runs late
Late-arriving aircraft accounts for 44% of the 6,845 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 41%Carrier
- 15%National Airspace System
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,845 reported delay minutes here, that single category outweighs weather by 44 to one. The split is drawn from 6,845 delay minutes reported on YX 3598.
Cancellations run at 4.31%, against 1.89% 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 routes
What a delay on this flight costs
9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The same number turns up on three other city pairs in the data, including BHM to ORD (20), STL to ORD (16) and ORD to STL (6), but none flew often enough under YX 3598 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to SDF only.
One caution: this is a thin sample. 348 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 YX 3598
For a booking, the cancellation rate is the figure to plan around on YX 3598: 4.31% of its 348 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ORD to SDF, every carrier and departure
- SDF to ORD, the return direction
- Republic Airways 3551 on the same route76.1%
- Republic Airways 4603 on the same route75.3%
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on-time record
- Every Republic Airways flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Republic Airways’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.