Flight number record
YX 4549
Republic Airways · Louisville to Washington
- Route
- SDF → DCA
- Departs
- 06:00
- Flights
- 364
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 364 flights, with a median arrival 10 minutes early.
Set against the rest of the country, YX 4549's record is 14 points better than the US average of 77.6%. That gap is worth roughly 140 fewer late arrivals for every thousand flights.
Key figures
On time
91.6%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
1.37%
National rate is 1.81%
1 hour+ late
2.5%
National rate is 8.1%
These figures cover 364 flights between July 2025 and June 2026. The median arrival is 10 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.
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 168 of 364 flights, with 06:01 (56 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 06:00168 flights46.2%
- Departs 06:0156 flights15.4%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
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 2 points better at 91.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
YX 4549 next to SDF to DCA
Every carrier on SDF to DCA combined arrived on time 78.9% of the time across 1,029 flights, so YX 4549 is 13 points ahead of it. Across its whole network Republic Airways managed 78.5%, which this flight beats by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| YX 4549thin sample | 364 | 91.6% | 66 min | 1.37% | A |
| All Republic Airways on SDF–DCA | 439 | 86.3% | 56 min | 1.59% | A |
| All carriers on SDF–DCA | 1,029 | 78.9% | 96 min | 4.66% | B− |
| Republic Airways, whole network | 361,482 | 78.5% | 72 min | 4.08% | B− |
Across the year
YX 4549 quarter by quarter
Quarter by quarter YX 4549 held fairly steady: 93.5% in Jul–Sep 2025, 89.0% in Oct–Dec 2025, 92.9% in Jan–Mar 2026 and 91.2% in Apr–Jun 2026. A spread of 5 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202592 flights93.5%
- Oct–Dec 202592 flights89.0%
- Jan–Mar 202689 flights92.9%
- Apr–Jun 202691 flights91.2%
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, YX 4549 ranged from 84.6% on Saturday to 96.1% on Wednesday. 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.
Delay causes
Why YX 4549 runs late
One category carries most of the weight here. Carrier accounts for 57% of the 1,989 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.
- 57%Carrier
- 27%National Airspace System
- 13%Late-arriving aircraft
- 3%Extreme weather
The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,132 of the 1,989 delay minutes reported here. The split is drawn from 1,989 delay minutes reported on YX 4549.
Cancellations sit at 1.37% against a national 1.81%, 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 2.5% land an hour or more behind schedule, against 8.1% 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, YX 4549 has one of the better records a US domestic flight can show: 91.6% on time and 1.37% cancelled. That is a base rate, not a promise about any single 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.