Flight number record
DL 1646
Delta Air Lines · Atlanta to Detroit
- Route
- ATL → DTW
- Departs
- 07:25
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1646, check with Delta Air Lines.
DL 1646 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 13 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 45 minutes. That rests on 364 flights, with a median arrival 6 minutes early.
Set against the rest of the country, DL 1646's record is 13 points better than the US average of 77.3%. That gap is worth roughly 133 fewer late arrivals for every thousand flights.
Key figures
On time
90.6%
Arrivals under 15 minutes late, of 361 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
1.7%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 6 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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Schedule
When DL 1646 flies
DL 1646 flies ATL to DTW without a single fixed slot. Its most common scheduled departure was 07:25, used on 204 of 364 flights, with 07:00 (67 flights) and 07:30 (63 flights) next.
- Departs 07:25204 flights56.0%
- Departs 07:0067 flights18.4%
- Departs 07:3063 flights17.3%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:25 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1646 runs level with that at 90.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1646 next to ATL to DTW
Every carrier on ATL to DTW combined arrived on time 76.4% of the time across 4,821 flights, so DL 1646 is 14 points ahead of it. Delta flew 3,774 flights on the same city pair under all its flight numbers, including this one, and those ran 77.9% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1646thin sample | 364 | 90.6% | 46 min | 0.55% | A+ |
| All Delta Air Lines on ATL–DTW | 3,774 | 77.9% | 60 min | 0.50% | B+ |
| All carriers on ATL–DTW | 4,821 | 76.4% | 64 min | 0.81% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1646 quarter by quarter
Quarter by quarter DL 1646 held fairly steady: 93.3% in Jul–Sep 2025, 90.1% in Oct–Dec 2025, 89.8% in Jan–Mar 2026, 92.2% in Apr–Jun 2026 and 88.7% in Jul–Sep 2026. A spread of 5 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights93.3%
- Oct–Dec 202591 flights90.1%
- Jan–Mar 202690 flights89.8%
- Apr–Jun 202691 flights92.2%
- Jul–Sep 202662 flights88.7%
Scale runs 80% to 100%.
By weekday, DL 1646 did best on Wednesday at 98.0% on time and worst on Sunday at 82.4%. Each day rests on about 52 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1646 runs when it is late
Most of the lateness is short. 19 of the 34 late arrivals were under half an hour behind, and 6 reached an hour or more.
- 15+ min early66 flights18.3%
- Within 15 min261 flights72.3%
- 15–29 min late19 flights5.3%
- 30–59 min late9 flights2.5%
- 1–2 hours late4 flights1.1%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 361 completed flights by arrival against schedule.
A late pushback is often recovered here: of 39 departures that left 15 minutes late or more, 15 still arrived on time. 10 flights left on time and still arrived late.
The worst days
Worst days for DL 1646
The latest arrival of the period was on 16 March 2026, 5 hours 16 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across March, December and July, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 16 March 2026 | 5 hours 16 minutes | Extreme weather |
| 5 December 2025 | 2 hours 56 minutes | National Airspace System |
| 25 July 2026 | 1 hour 30 minutes | Carrier |
| 7 December 2025 | 1 hour 29 minutes | National Airspace System |
| 24 March 2026 | 1 hour 17 minutes | Carrier |
Delay causes
Why DL 1646 runs late
Carrier accounts for 45% of the 1,555 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Carrier
- 31%National Airspace System
- 20%Extreme weather
- 3%Late-arriving aircraft
Extreme weather accounts for 20% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.4 times the usual weather exposure. The split is drawn from 1,555 delay minutes reported on DL 1646.
Cancellations are rare at 0.55%, below the national 1.89% 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 routes
What a delay on this flight costs
Badly late arrivals are rare here: only 1.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 594 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
Every one of the 364 flights under DL 1646 in the data flew ATL to DTW. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 364 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 DL 1646
For a booking, DL 1646 has one of the better records a US domestic flight can show: 90.6% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- ATL to DTW, every carrier and departure
- DTW to ATL, the return direction
- Delta Air Lines 1298 on the same route84.3%
- Delta Air Lines 1031 on the same route83.9%
- Delta Air Lines 1240 on the same route82.7%
- Delta Air Lines 1005 on the same route75.2%
- Delta Air Lines 2940 on the same route72.6%
- Delta Air Lines 2067 on the same route74.6%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.