Carrier route record

WNATL→IND

Southwest Airlines · Atlanta to Indianapolis

Flights: 330
Period: July 2025 to June 2026
Share of route: 10%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on ATL to IND lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That is a workable record, not a spotless one. That rests on 330 flights, with a median arrival 2 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on ATL to IND from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

79.5%

Arrivals under 15 minutes late, of 327 completed flights

Avg delay

53 min

Across delayed arrivals only, not all flights

Cancelled

0.61%

National rate is 1.81%

Whole route

82.7%

Every carrier on ATL to IND, 3,190 flights

These figures cover 330 flights between July 2025 and June 2026. The median arrival is 2 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.

Carrier by carrier

Southwest against every carrier on ATL to IND

Southwest flew 330 of the 3,190 flights on ATL to IND, about 10% of it. Its 79.5% on time is 3 points worse than the route as a whole, which runs 82.7%. Ranked by on-time rate it is number two of five carriers on the route, where the range runs from Delta at 84.0% to American at 0.0%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on ATL to IND
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	2,711	84.0%	55 min	1.48%	B
Southwest Airlines (this page)thin sample	330	79.5%	53 min	0.61%	B+
Spirit Airlinesthin sample	7	71.4%	148 min	0.00%	C+
Frontier Airlinesthin sample	141	67.9%	71 min	0.71%	C+
American Airlinesthin sample	1	0.0%	70 min	0.00%	F+

Departure window

When Southwest runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 330 flights.

5am–8am—
8am–11am1 flights—
11am–2pm88 flights80.5%
2pm–5pm182 flights80.7%
5pm–8pm59 flights74.1%
8pm–5am—

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 2pm–5pm slot at 80.7% on time, ahead of 5pm–8pm at 74.1%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 182 flights scheduled in it.

Across the year

Southwest on ATL to IND through the year

Jul–Sep 202592 flights81.1%
Oct–Dec 202592 flights83.7%
Jan–Mar 202687 flights82.6%
Apr–Jun 202659 flights66.1%

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 79.5% on time across 330 flights.

Southwest on ATL to IND did not run the same all year. Its best quarter was Oct–Dec 2025 at 83.7% on time and its weakest Apr–Jun 2026 at 66.1%, a swing of 18 points on roughly 83 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.

Across the week, Wednesday is the strongest day at 92.3% on time and Sunday the weakest at 72.5%. 20 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 60% of the 3,540 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.

Late-arriving aircraft
60%
Carrier
28%
National Airspace System
10%
Extreme weather
2%

60% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 3,540 reported delay minutes here, that single category outweighs weather by 25 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 3,540 reported delay minutes.

Cancellations are rare at 0.61%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

5.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.

At 432 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 2pm–5pm window matters as much as it does.

The return leg runs 79.5% on time across 328 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 330 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 Southwest on ATL to IND

Put together: treat all of this as provisional. 330 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 79.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 327 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures