Flight number record
YX 4549
Republic Airways · Louisville to Washington
- Route
- SDF → DCA
- Departs
- 06:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s YX 4549, 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 4549 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 364 flights, with a median arrival 12 minutes early.
Set against the rest of the country, YX 4549's record is 12 points better than the US average of 77.3%. That gap is worth roughly 124 fewer late arrivals for every thousand flights.
Key figures
On time
89.7%
Arrivals under 15 minutes late, of 358 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
1.65%
National rate is 1.89%
1 hour+ late
3.1%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 12 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When YX 4549 flies
YX 4549 flies SDF to DCA without a single fixed slot. Its most common scheduled departure was 06:00, used on 197 of 364 flights, with 06:01 (57 flights) next.
- Departs 06:00197 flights54.1%
- Departs 06:0157 flights15.7%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and YX 4549 runs level with that at 89.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
YX 4549 next to SDF to DCA
Every carrier on SDF to DCA combined arrived on time 78.2% of the time across 1,025 flights, so YX 4549 is 12 points ahead of it. Across its whole network Republic Airways managed 78.1%, which this flight beats by 12 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| YX 4549thin sample | 364 | 89.7% | 57 min | 1.65% | A |
| All Republic Airways on SDF–DCA | 463 | 83.4% | 53 min | 2.16% | B |
| All carriers on SDF–DCA | 1,025 | 78.2% | 87 min | 4.59% | B− |
| Republic Airways, whole network | 364,452 | 78.1% | 74 min | 4.55% | B− |
Across the year
YX 4549 quarter by quarter
Quarter by quarter YX 4549 held fairly steady: 90.0% in Jul–Sep 2025, 89.0% in Oct–Dec 2025, 92.9% in Jan–Mar 2026, 91.2% in Apr–Jun 2026 and 83.6% in Jul–Sep 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights90.0%
- Oct–Dec 202592 flights89.0%
- Jan–Mar 202689 flights92.9%
- Apr–Jun 202691 flights91.2%
- Jul–Sep 202662 flights83.6%
Scale runs 75% to 100%.
By weekday, YX 4549 ranged from 82.4% on Saturday to 94.2% on Thursday. With about 52 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late YX 4549 runs when it is late
YX 4549 often beats the schedule: 137 of 358 completed flights, 38%, arrived 15 minutes or more early. The 37 late arrivals split 15 under half an hour, 11 between 30 and 60 minutes, and 11 an hour or more.
- 15+ min early137 flights38.3%
- Within 15 min184 flights51.4%
- 15–29 min late15 flights4.2%
- 30–59 min late11 flights3.1%
- 1–2 hours late7 flights2.0%
- 2+ hours late4 flights1.1%
Scale runs 0% to 100%.
Share of 358 completed flights by arrival against schedule.
5 of 23 late departures made up the time and arrived on time, 22% of them. In the other direction, 19 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 DCA.
The worst days
Worst days for YX 4549
The latest arrival of the period was on 23 June 2026, 3 hours 49 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 23 June 2026 | 3 hours 49 minutes | Carrier |
| 2 December 2025 | 2 hours 52 minutes | National Airspace System |
| 3 January 2026 | 2 hours 47 minutes | Carrier |
| 27 July 2026 | 2 hours 9 minutes | Carrier |
| 2 February 2026 | 1 hour 45 minutes | Carrier |
Delay causes
Why YX 4549 runs late
Carrier accounts for 65% of the 2,093 delay minutes carriers reported here, and the remaining four split what is left.
- 65%Carrier
- 32%National Airspace System
- 3%Extreme weather
32% 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 678 minutes out of 2,093, against a national NAS share of 21%. The split is drawn from 2,093 delay minutes reported on YX 4549.
Cancellations sit at 1.65% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.1% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
Every one of the 364 flights under YX 4549 in the data flew SDF to DCA. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 364 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 4549
For a booking, read YX 4549 as 89.7% on time with 1.65% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SDF to DCA, every carrier and departure
- DCA to SDF, the return direction
- Ronald Reagan Washington National (DCA) 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
- Worst months to fly in the US, ranked by the data
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.