Delta vs Southwest: On-Time Performance Compared

Last 12 months · Aug 2025 – Jul 2026

Data through July 2026 · Last updated October 18, 2026

Over the last 12 months 81.5% of Delta flights arrived on time, compared with 76.4% for Southwest.

Southwest cancelled fewer flights (0.9% vs 1.7%), and late flights averaged 71 minutes late on Delta vs 53 on Southwest.

On the 164 routes both airlines fly regularly, Delta had the better on-time record on 149 and Southwest on 15.

Delta vs Southwest: key numbers

Last 12 months, all flights each airline operated.

DeltaSouthwest

On-time arrivals81.5%76.4%

On-time departures81.9%71.8%

Cancelled1.7%0.9%

Diverted0.3%0.2%

On-time arrival % each month, last 24 months.

DeltaSouthwest

60%70%80%90%

Aug ’24Nov ’24Feb ’25May ’25Aug ’25Nov ’25Feb ’26May ’26

Share of each airline’s reported delay minutes by cause, last 12 months.

DeltaSouthwest

Airline (carrier)44.7%28.4%

Weather4.1%2.3%

Air traffic system (NAS)21.6%17.9%

Security0.1%0.3%

Late-arriving aircraft29.5%51.1%

164 routes where each airline had at least 100 completed flights in the last 12 months; the 25 busiest are shown. Better on-time rate in bold.

Route	Delta on time	Southwest on time	Delta flights	Southwest flights
ATL → MCO	70.8%	74.9%	5,480	1,095
MCO → ATL	78.8%	69.8%	5,478	1,093
ATL → LGA	76.7%	71.2%	4,935	815
LGA → ATL	80.0%	75.2%	4,932	815
ATL → TPA	75.2%	75.1%	4,401	731
TPA → ATL	81.7%	76.7%	4,401	731
ATL → DCA	67.8%	71.8%	3,842	1,107
DCA → ATL	80.7%	79.2%	3,842	1,106
BWI → ATL	86.5%	77.4%	2,811	1,566
ATL → BWI	78.7%	78.1%	2,811	1,562
ATL → BNA	81.2%	77.3%	3,369	899
BNA → ATL	86.5%	72.4%	3,368	897
ATL → AUS	81.1%	82.9%	3,202	1,036
AUS → ATL	85.7%	78.5%	3,201	1,036
LAS → LAX	84.0%	68.9%	1,737	2,382
LAX → LAS	79.0%	71.2%	1,735	2,377
LAS → ATL	86.5%	82.9%	3,322	720
ATL → LAS	77.6%	76.4%	3,322	719
RDU → ATL	88.8%	90.7%	3,802	216
ATL → RDU	82.8%	86.8%	3,801	216
DEN → SLC	83.4%	72.8%	1,696	2,307
SLC → DEN	80.9%	72.8%	1,696	2,306
DEN → ATL	86.0%	64.4%	2,810	1,076
ATL → DEN	79.4%	73.3%	2,810	1,075
LAX → SFO	62.9%	53.9%	2,374	1,426