Carrier route record
DLSTL→DTW
Delta Air Lines · St. Louis to Detroit
- 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 STL to DTW earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 1,104 flights, with a median arrival 15 minutes early.
Set against the rest of the country, Delta's STL to DTW record is 11 points better than the US average of 77.3%. That gap is worth roughly 109 fewer late arrivals for every thousand flights.
Key figures
On time
88.2%
Arrivals under 15 minutes late, of 1,082 completed flights
Avg delay
111 min
Across delayed arrivals only, not all flights
Cancelled
1.81%
National rate is 1.89%
Whole route
81.1%
Every carrier on STL to DTW, 1,899 flights
These figures cover 1,104 flights between September 2025 and August 2026. The median arrival is 15 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 STL to DTW
Delta flew 1,104 of the 1,899 flights on STL to DTW, most of the route. Its 88.2% on time is 7 points better than the route as a whole, which runs 81.1%. 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 71.3%. 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 | 88.2% | 111 min | 1.81% | A |
| Southwest Airlines | 611 | 71.5% | 59 min | 0.16% | C+ |
| SkyWest Airlinesthin sample | 183 | 71.3% | 110 min | 1.09% | C |
Flight by flight
Delta flight numbers on STL to DTW
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 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 1,104 flights.
- 5am–8am348 flights91.7%
- 8am–11am246 flights90.9%
- 11am–2pm—
- 2pm–5pm159 flights82.8%
- 5pm–8pm351 flights85.2%
- 8pm–5am—
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.7% of the time, against 82.8% for the afternoon window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 351 flights scheduled in it.
Across the year
Delta on STL to DTW through the year
July is the worst month at 78.1% on time, 20 points below September, the best at 97.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 118 flights.
Across the week, Wednesday is the strongest day at 93.3% on time and Monday the weakest at 81.6%, a spread of 12 points.
Arrival by arrival
How late Delta on STL to DTW runs when it is late
Delta on STL to DTW often beats the schedule: 542 of 1,082 completed flights, 50%, arrived 15 minutes or more early. When Delta on STL to DTW is late it tends to be very late: 66 of its 128 late arrivals were an hour or more behind, and 37 were two hours or more.
- 15+ min early542 flights50.1%
- Within 15 min412 flights38.1%
- 15–29 min late29 flights2.7%
- 30–59 min late33 flights3.0%
- 1–2 hours late29 flights2.7%
- 2+ hours late37 flights3.4%
Scale runs 0% to 100%.
Share of 1,082 completed flights by arrival against schedule.
29 of 147 late departures made up the time and arrived on time, 20% of them. Only 10 left on time and still arrived late.
The worst days
Worst days for Delta on STL to DTW
The latest arrival of the period was on 1 December 2025, 19 hours 4 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 December 2025 | 19 hours 4 minutes | Carrier |
| 11 August 2026 | 12 hours 11 minutes | Carrier |
| 10 August 2026 | 8 hours 47 minutes | Carrier |
| 4 June 2026 | 7 hours 38 minutes | Carrier |
| 30 October 2025 | 7 hours 2 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Carrier accounts for 58% of the 14,000 delay minutes carriers reported here, and the remaining four split what is left.
- 58%Carrier
- 32%Late-arriving aircraft
- 7%National Airspace System
- 3%Extreme weather
The largest share of delay minutes, 58%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 8,244 of the 14,000 delay minutes reported here. The split is drawn from 14,206 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.7% on time here.
Cancellations sit at 1.81% against a national 1.89%, which is ordinary. Diversions add another 0.18%.
Connections and stage length
What a delay here costs
6.1% 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 close to two hours, 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 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 80.4% on time across 1,104 flights, 8 points below 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 STL to DTW
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 97.9% on time and July 78.1%, a swing of 20 points. If the dates move at all, move them out of July before you think about anything else. 1,082 completed flights over 12 months sit behind that.
Related
Where to go next
- STL to DTW, every carrier
- Delta on DTW to STL, the return leg
- Southwest Airlines on STL to DTW71.5%
- SkyWest Airlines on STL to DTW71.3%
- Delta Air Lines network-wide record
- St. Louis Lambert International (STL) 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 7.05 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.