Louisville Muhammad Ali International in September 2025

86.5%departed on time

BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.

In September 2025, reporting carriers scheduled 1,929 domestic departures from Louisville Muhammad Ali International (SDF). 86.5% left less than 15 minutes late and 87.1% reached their destination on time; 0.7% were cancelled.

Nationally that month, 83.1% of flights departed on time and 82.8% arrived on time, so SDF departures were 3.4 points above the national departure figure.

A year earlier, in September 2024, the airport had 2,025 departures with 86.5% leaving on time: a change of 0.0 points, with flights down 5%.

Flights arriving at SDF that month were on time 86.0% of the time (1,928 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, air carrier 47%, late-arriving aircraft 26% and national aviation system 24%.

On time 87.1%
Arrived 15+ minutes late 11.9%
Cancelled 0.7%
Diverted 0.2%

Every scheduled departure from SDF in September 2025, judged by arrival at the destination.

September 2025 against a year earlier, the airport's year and the nation

Measure	Sep 2025	Sep 2024	SDF, 12 months to Jul 2026	All reported flights, Sep 2025
Departed on time	86.5%	86.5%	80.0%	83.1%
Arrived on time	87.1%	84.5%	79.7%	82.8%
Cancelled	0.7%	0.4%	2.2%	0.5%
Average departure delay (late minutes only)	12.1 min	10.8 min	15.9 min	12.2 min
Scheduled departures a day	64	68	63	18,748
Scheduled departures	1,929	2,025	23,144	562,439

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
YX Republic Airline	421	22%	87.9%	-2.9 min	1.0%
WN Southwest Airlines	391	20%	90.0%	-3.6 min	0.3%
DL Delta Air Lines	222	12%	98.6%	-15.7 min	0.0%
OH PSA Airlines	222	12%	83.3%	12.0 min	0.5%
AA American Airlines	206	11%	76.2%	25.9 min	3.4%
OO SkyWest Airlines	147	8%	91.2%	-8.8 min	0.0%
MQ Envoy Air	134	7%	73.9%	6.6 min	0.7%
NK Spirit Airlines	73	4%	89.0%	1.4 min	0.0%
UA United Airlines	60	3%	90.0%	-4.2 min	0.0%
G4 Allegiant Air	53	3%	86.8%	-2.7 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
SDF–ATL	Louisville to Atlanta	222	98.6%	-15.7 min	0.0%
SDF–ORD	Louisville to Chicago	222	89.2%	-3.6 min	0.5%
SDF–DFW	Louisville to Dallas/Fort Worth	180	74.4%	19.4 min	3.3%
SDF–CLT	Louisville to Charlotte	159	85.5%	27.0 min	0.6%
SDF–LGA	Louisville to New York	98	91.8%	-6.4 min	1.0%
SDF–DCA	Louisville to Washington	90	81.1%	0.7 min	1.1%
SDF–DEN	Louisville to Denver	90	92.2%	-5.4 min	0.0%
SDF–MDW	Louisville to Chicago	86	94.2%	-9.8 min	0.0%
SDF–BWI	Louisville to Baltimore	77	87.0%	2.4 min	0.0%
SDF–DTW	Louisville to Detroit	73	93.2%	-7.9 min	0.0%
SDF–PHL	Louisville to Philadelphia	66	89.4%	-6.9 min	0.0%
SDF–EWR	Louisville to Newark	63	90.5%	-7.9 min	1.6%

By scheduled departure hour

On-time share:under 62%6270768288% and over

Share of departures that left less than 15 minutes late, by scheduled hour (local time), September 2025.

Delay causes

BTS cause category	Share of delay minutes	National, Sep 2025	Minutes
Air carrier	47.0%	34.3%	10,245
Late-arriving aircraft	25.6%	37.4%	5,573
National Aviation System	23.5%	22.6%	5,125
Extreme weather	3.9%	5.6%	859
Security	0.0%	0.1%	3

21,805 delay minutes on 230 flights that arrived 15 or more minutes late and carried a cause report. Carriers assign the categories; see what each category means.

Questions and answers

How many flights left SDF on time in September 2025?

86.5% of 1,929 scheduled domestic departures left less than 15 minutes late, and 87.1% reached their destination on time. The national figures that month were 83.1% and 82.8%.

How does that compare with a year earlier?

In September 2024, 86.5% of 2,025 departures left on time and 0.4% were cancelled, against 86.5% and 0.7% in September 2025.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for September 2025; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for SDF · methodology · corrections.