Flight number record

YX 5643

Republic Airways · New York to Louisville

Route: LGA → SDF
Departs: 08:30
Flights: 266
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s YX 5643, 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 5643 earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 40 minutes. That rests on 266 flights, with a median arrival 12 minutes early.

Set against the rest of the country, YX 5643's record is 8 points better than the US average of 77.3%. That gap is worth roughly 84 fewer late arrivals for every thousand flights.

On time

85.7%

Arrivals under 15 minutes late, of 259 completed flights

Avg delay

41 min

Across delayed arrivals only, not all flights

Cancelled

2.63%

National rate is 1.89%

1 hour+ late

3.1%

National rate is 8.3%

These figures cover 266 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.

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Schedule

When YX 5643 flies

YX 5643 flies LGA to SDF without a single fixed slot. Its most common scheduled departure was 08:30, used on 41 of 266 flights, with 09:00 (31 flights) and 08:15 (30 flights) next.

Departs 08:3041 flights15.4%
Departs 09:0031 flights11.7%
Departs 08:1530 flights11.3%

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 08:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and YX 5643 runs level with that at 85.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

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Against the route

YX 5643 next to LGA to SDF

Every carrier on LGA to SDF combined arrived on time 79.9% of the time across 1,033 flights, so YX 5643 is 6 points ahead of it. Republic flew 1,032 flights on the same city pair under all its flight numbers, including this one, and those ran 80.0% on time. Across its whole network Republic Airways managed 78.1%, which this flight beats by 8 points.

YX 5643 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
YX 5643thin sample	266	85.7%	41 min	2.63%	A
All Republic Airways on LGA–SDF	1,032	80.0%	60 min	3.97%	B−
All carriers on LGA–SDF	1,033	79.9%	60 min	3.97%	B−
Republic Airways, whole network	364,452	78.1%	74 min	4.55%	B−

Across the year

YX 5643 quarter by quarter

YX 5643 did not run the same all year. Its best quarter was Jul–Sep 2026 at 89.8% on time and its weakest Oct–Dec 2025 at 78.0%, a swing of 12 points on roughly 67 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 202527 flights—
Oct–Dec 202551 flights78.0%
Jan–Mar 202636 flights84.8%
Apr–Jun 202690 flights85.6%
Jul–Sep 202662 flights89.8%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, YX 5643 did best on Monday at 91.7% on time and worst on Thursday at 78.8%. Each day rests on about 38 flights, so a gap of 13 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late YX 5643 runs when it is late

YX 5643 often beats the schedule: 104 of 259 completed flights, 40%, arrived 15 minutes or more early. The 37 late arrivals split 18 under half an hour, 11 between 30 and 60 minutes, and 8 an hour or more.

15+ min early104 flights40.2%
Within 15 min118 flights45.6%
15–29 min late18 flights6.9%
30–59 min late11 flights4.2%
1–2 hours late6 flights2.3%
2+ hours late2 flights0.8%

Scale runs 0% to 100%.

Share of 259 completed flights by arrival against schedule.

A late pushback is often recovered here: of 34 departures that left 15 minutes late or more, 11 still arrived on time. In the other direction, 14 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 5643

The latest arrival of the period was on 3 April 2026, 2 hours 6 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across April, September, December and August, with no single month standing out.

The latest arrivals of YX 5643 in the period
Date	Arrived late by	Largest filed cause
3 April 2026	2 hours 6 minutes	Late-arriving aircraft
26 September 2025	2 hours 2 minutes	Extreme weather
15 December 2025	1 hour 31 minutes	Carrier
2 August 2026	1 hour 22 minutes	Late-arriving aircraft
27 August 2026	1 hour 6 minutes	National Airspace System

Delay causes

Why YX 5643 runs late

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 1,514 reported delay minutes.

Carrier
37%
National Airspace System
33%
Late-arriving aircraft
22%
Extreme weather
8%

33% 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 498 minutes out of 1,514, against a national NAS share of 21%. The split is drawn from 1,514 delay minutes reported on YX 5643.

Cancellations run at 2.63%, against 1.89% nationally. That is about 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 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.

The 659 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.

The same number turns up on two other city pairs in the data, including SDF to LGA (241) and SDF to BOS (6), but none flew often enough under YX 5643 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LGA to SDF only.

One caution: this is a thin sample. 266 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 5643

For a booking, the cancellation rate is the figure to plan around on YX 5643: 2.63% of its 266 scheduled flights did not operate. A late arrival costs about 40 minutes, but a cancellation costs the day, so leave a later option open.

Where to go next

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 22 October 2026; recomputed monthly. How this data is collected.

Key figures