Flight number record

DL 1639

Delta Air Lines · Charlotte to Detroit

Route: CLT → DTW
Departs: 09:45
Flights: 275
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1639, check with Delta Air Lines.

DL 1639 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 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 275 flights, with a median arrival 17 minutes early.

Set against the rest of the country, DL 1639's record is 14 points better than the US average of 77.6%. That gap is worth roughly 139 fewer late arrivals for every thousand flights.

On time

91.5%

Arrivals under 15 minutes late, of 271 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

1.09%

National rate is 1.81%

1 hour+ late

3.3%

National rate is 8.1%

These figures cover 275 flights between July 2025 and June 2026. The median arrival is 17 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 1639 flies

DL 1639 flies CLT to DTW without a single fixed slot. Its most common scheduled departure was 09:45, used on 62 of 275 flights, with 09:38 (31 flights) and 09:32 (29 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 09:4562 flights22.5%
Departs 09:3831 flights11.3%
Departs 09:3229 flights10.5%

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 09:45 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 1639 runs 7 points better at 91.5%. 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 1639 next to CLT to DTW

Every carrier on CLT to DTW combined arrived on time 82.2% of the time across 3,535 flights, so DL 1639 is 9 points ahead of it. Delta flew 1,344 flights on the same city pair under all its flight numbers, including this one, and those ran 88.1% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 10 points.

DL 1639 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1639thin sample	275	91.5%	83 min	1.09%	A
All Delta Air Lines on CLT–DTW	1,344	88.1%	84 min	1.34%	A
All carriers on CLT–DTW	3,535	82.2%	75 min	1.64%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1639 quarter by quarter

Quarter by quarter DL 1639 held fairly steady: 92.3% in Jul–Sep 2025, 89.6% in Oct–Dec 2025, 92.3% in Jan–Mar 2026 and 91.7% in Apr–Jun 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202579 flights92.3%
Oct–Dec 202568 flights89.6%
Jan–Mar 202679 flights92.3%
Apr–Jun 202649 flights91.7%

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

By weekday, DL 1639 ranged from 86.7% on Wednesday to 97.7% on Thursday. With about 39 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 1639 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 73% of the 1,915 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.

Late-arriving aircraft
73%
Carrier
23%
National Airspace System
4%

73% 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 1,915 reported delay minutes here, that single category outweighs weather by 73 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 1,915 delay minutes reported on DL 1639.

Cancellations sit at 1.09% against a national 1.81%, which is ordinary. Diversions add another 0.36%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 3.3% 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 500 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.

The same number turns up on two other city pairs in the data, including MSY to LGA (12) and DTW to CLT (5), but none flew often enough under DL 1639 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to CLT to DTW only.

One caution: this is a thin sample. 275 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 1639

For a booking, DL 1639 has one of the better records a US domestic flight can show: 91.5% on time and 1.09% 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