Flight number record

DL 1646

Delta Air Lines · Atlanta to Detroit

Route: ATL → DTW
Departs: 07:25
Flights: 364
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 15 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 364 flights, with a median arrival 8 minutes early.

Set against the rest of the country, DL 1646's record is 15 points better than the US average of 77.6%. That gap is worth roughly 146 fewer late arrivals for every thousand flights.

On time

92.2%

Arrivals under 15 minutes late, of 360 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.82%

National rate is 1.81%

1 hour+ late

1.4%

National rate is 8.1%

These figures cover 364 flights between July 2025 and June 2026. The median arrival is 8 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.

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 231 of 364 flights, with 07:30 (62 flights) and 07:00 (45 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:25231 flights63.5%
Departs 07:3062 flights17.0%
Departs 07:0045 flights12.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 3 points better at 92.2%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 1646 next to ATL to DTW

Every carrier on ATL to DTW combined arrived on time 78.0% of the time across 4,871 flights, so DL 1646 is 14 points ahead of it. Delta flew 3,698 flights on the same city pair under all its flight numbers, including this one, and those ran 79.5% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 11 points.

DL 1646 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1646thin sample	364	92.2%	49 min	0.82%	A+
All Delta Air Lines on ATL–DTW	3,698	79.5%	57 min	0.51%	B+
All carriers on ATL–DTW	4,871	78.0%	63 min	0.82%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1646 quarter by quarter

Quarter by quarter DL 1646 held fairly steady: 96.7% in Jul–Sep 2025, 90.1% in Oct–Dec 2025, 89.8% in Jan–Mar 2026 and 92.2% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights96.7%
Oct–Dec 202591 flights90.1%
Jan–Mar 202690 flights89.8%
Apr–Jun 202691 flights92.2%

Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1646 ranged from 86.8% on Tuesday to 98.0% on Wednesday. With about 52 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why DL 1646 runs late

One category carries most of the weight here. Carrier accounts for 44% of the 1,382 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.

Carrier
44%
National Airspace System
30%
Extreme weather
23%
Late-arriving aircraft
4%

Extreme weather accounts for 23% 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 3.7 times the usual weather exposure. The split is drawn from 1,382 delay minutes reported on DL 1646.

Cancellations are rare at 0.82%, 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 routes

What a delay on this flight costs

Badly late arrivals are rare here: only 1.4% land an hour or more behind schedule, against 8.1% 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

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: 92.2% on time and 0.82% cancelled. That is a base rate, not a promise about any single day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures