Carrier route record
DLDTW→STL
Delta Air Lines · Detroit to St. Louis
- Flights
- 1,104
- Period
- September 2025 to August 2026
- Share of route
- 58%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on DTW to STL lands a B, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,104 flights, with a median arrival 10 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on DTW to STL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.4%
Arrivals under 15 minutes late, of 1,084 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
1.27%
National rate is 1.89%
Whole route
76.6%
Every carrier on DTW to STL, 1,899 flights
These figures cover 1,104 flights between September 2025 and August 2026. The median arrival is 10 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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Carrier by carrier
Delta against every carrier on DTW to STL
Delta flew 1,104 of the 1,899 flights on DTW to STL, most of the route. Its 80.4% on time is 4 points better than the route as a whole, which runs 76.6%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Spirit at 100.0% to SkyWest at 61.2%. 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 |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines (this page) | 1,104 | 80.4% | 63 min | 1.27% | B |
| Southwest Airlines | 611 | 74.3% | 55 min | 0.65% | C+ |
| SkyWest Airlinesthin sample | 183 | 61.2% | 87 min | 1.64% | D |
Flight by flight
Delta flight numbers on DTW to STL
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am246 flights87.7%
- 11am–2pm183 flights81.1%
- 2pm–5pm291 flights79.6%
- 5pm–8pm83 flights78.0%
- 8pm–5am301 flights75.2%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 87.7% of the time, against 75.2% for the overnight window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 301 flights scheduled in it.
Across the year
Delta on DTW to STL through the year
December is the weak month at 67.9% on time, against 90.6% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. August was the busiest month here, with 118 flights.
Across the week, Saturday is the strongest day at 87.9% on time and Sunday the weakest at 71.7%, a spread of 16 points.
Arrival by arrival
How late Delta on DTW to STL runs when it is late
Delta on DTW to STL often beats the schedule: 384 of 1,084 completed flights, 35%, arrived 15 minutes or more early. The 213 late arrivals split 66 under half an hour, 77 between 30 and 60 minutes, and 70 an hour or more.
- 15+ min early384 flights35.4%
- Within 15 min487 flights44.9%
- 15–29 min late66 flights6.1%
- 30–59 min late77 flights7.1%
- 1–2 hours late41 flights3.8%
- 2+ hours late29 flights2.7%
Scale runs 0% to 100%.
Share of 1,084 completed flights by arrival against schedule.
40 of 231 late departures made up the time and arrived on time, 17% of them. 22 flights left on time and still arrived late.
The worst days
Worst days for Delta on DTW to STL
The latest arrival of the period was on 6 February 2026, 10 hours 34 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 February 2026 | 10 hours 34 minutes | Carrier |
| 28 October 2025 | 6 hours 26 minutes | Carrier |
| 5 July 2026 | 5 hours 12 minutes | Late-arriving aircraft |
| 22 July 2026 | 4 hours 28 minutes | Late-arriving aircraft |
| 27 March 2026 | 4 hours 12 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Carrier accounts for 54% of the 14,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 33%Late-arriving aircraft
- 12%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,305 of the 14,000 delay minutes reported here. The split is drawn from 13,505 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.7% on time here.
Cancellations sit at 1.27% against a national 1.89%, which is ordinary. Diversions add another 0.54%.
Connections and stage length
What a delay here costs
6.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
At 440 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 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 88.2% on time across 1,104 flights, 8 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 8 points of difference.
The sample behind these figures is 1,104 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking Delta on DTW to STL
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.6% on time and December 67.9%, a swing of 23 points. If the dates move at all, move them out of December before you think about anything else. 1,084 completed flights over 12 months sit behind that.
Related
Where to go next
- DTW to STL, every carrier
- Delta on STL to DTW, the return leg
- Southwest Airlines on DTW to STL74.3%
- SkyWest Airlines on DTW to STL61.2%
- Delta Air Lines network-wide record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.