Carrier route record
WNBNA→DTW
Southwest Airlines · Nashville to Detroit
- Flights
- 846
- Period
- July 2025 to June 2026
- Share of route
- 35%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on BNA to DTW sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 10 points worse than the national rate of 77.6%. The late ones land about 45 minutes behind schedule. That rests on 846 flights, with a median arrival 4 minutes late.
The national on-time rate over the same period is 77.6%, so Southwest on BNA to DTW runs 10 points behind the country as a whole. Across a thousand flights that is about 96 extra late arrivals.
Key figures
On time
68.0%
Arrivals under 15 minutes late, of 844 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
0.24%
National rate is 1.81%
Whole route
79.1%
Every carrier on BNA to DTW, 2,420 flights
These figures cover 846 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
Carrier by carrier
Southwest against every carrier on BNA to DTW
Southwest flew 846 of the 2,420 flights on BNA to DTW, about 35% of it. Its 68.0% on time is 11 points worse than the route as a whole, which runs 79.1%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Delta at 86.1% to SkyWest at 50.0%. Two 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,404 | 86.1% | 99 min | 1.92% | A |
| Spirit Airlinesthin sample | 148 | 82.3% | 71 min | 0.68% | B+ |
| Southwest Airlines (this page) | 846 | 68.0% | 44 min | 0.24% | C+ |
| SkyWest Airlinesthin sample | 22 | 50.0% | 45 min | 0.00% | F+ |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am174 flights78.6%
- 11am–2pm190 flights83.7%
- 2pm–5pm62 flights55.7%
- 5pm–8pm300 flights62.3%
- 8pm–5am120 flights48.3%
Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 48.3% on time, against 83.7% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 300 flights scheduled in it.
Across the year
Southwest on BNA to DTW through the year
Delays peak in May, when the on-time rate falls to 50.6%. January is the strongest month at 83.6%. Moving a flexible trip across that boundary buys 33 points. May was the busiest month here, with 87 flights.
Across the week, Wednesday is the strongest day at 75.8% on time and Sunday the weakest at 60.6%. 15 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 62% of the 12,000 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.
- 62%Late-arriving aircraft
- 28%Carrier
- 8%National Airspace System
- 2%Extreme weather
- 1%Security
62% 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 12,000 reported delay minutes here, that single category outweighs weather by 41 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 11,983 reported delay minutes.
Cancellations are rare at 0.24%, 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
6.9% 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 about 45 minutes, which a normal layover absorbs.
At 456 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 11am–2pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 77.7% on time across 846 flights, 10 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.
One caution: this is a thin sample. 846 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 BNA to DTW
Put together: treat all of this as provisional. 846 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 68.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 844 completed flights over 12 months sit behind that.
Related
Where to go next
- BNA to DTW, every carrier
- Southwest on DTW to BNA, the return leg
- Delta Air Lines on BNA to DTW86.1%
- Spirit Airlines on BNA to DTW82.3%
- Southwest Airlines network-wide record
- Nashville International (BNA) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.