Flight number record

DL 421

Delta Air Lines · Detroit to Las Vegas

Route: DTW → LAS
Departs: 12:32
Flights: 361
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 421, check with Delta Air Lines.

DL 421 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 361 flights, with a median arrival right on schedule.

The national on-time rate over the same period is 77.3%, so DL 421 runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.

On time

72.4%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.89%

1 hour+ late

7.2%

National rate is 8.3%

These figures cover 361 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Schedule

When DL 421 flies

DL 421 flies DTW to LAS without a single fixed slot. Its most common scheduled departure was 12:32, used on 85 of 361 flights, with 12:20 (53 flights) and 12:15 (50 flights) next.

Departs 12:3285 flights23.5%
Departs 12:2053 flights14.7%
Departs 12:1550 flights13.9%

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 12:32 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 421 runs 6 points worse at 72.4%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

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Against the route

DL 421 next to DTW to LAS

Every carrier on DTW to LAS combined arrived on time 73.6% of the time across 2,768 flights, so DL 421 is about level with it. Delta flew 1,880 flights on the same city pair under all its flight numbers, including this one, and those ran 73.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 9 points.

DL 421 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 421thin sample	361	72.4%	52 min	0.55%	C+
All Delta Air Lines on DTW–LAS	1,880	73.8%	63 min	0.59%	C+
All carriers on DTW–LAS	2,768	73.6%	59 min	0.61%	C+
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 421 quarter by quarter

DL 421 did not run the same all year. Its best quarter was Apr–Jun 2026 at 79.1% on time and its weakest Jul–Sep 2026 at 50.0%, a swing of 29 points on roughly 72 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202530 flights73.3%
Oct–Dec 202589 flights78.7%
Jan–Mar 202689 flights74.2%
Apr–Jun 202691 flights79.1%
Jul–Sep 202662 flights50.0%

Scale runs 40% to 85%.

By weekday, DL 421 ranged from 67.3% on Tuesday to 76.5% on Friday. With about 52 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late DL 421 runs when it is late

The 99 late arrivals split 36 under half an hour, 37 between 30 and 60 minutes, and 26 an hour or more.

15+ min early59 flights16.4%
Within 15 min201 flights56.0%
15–29 min late36 flights10.0%
30–59 min late37 flights10.3%
1–2 hours late20 flights5.6%
2+ hours late6 flights1.7%

Scale runs 0% to 100%.

Share of 359 completed flights by arrival against schedule.

Time lost at the gate mostly stays lost. Of 80 departures that left 15 minutes late or more, only 8 made it up before arrival. In the other direction, 27 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at LAS.

The worst days

Worst days for DL 421

The latest arrival of the period was on 25 January 2026, 6 hours 9 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as a late-arriving aircraft.

The latest arrivals of DL 421 in the period
Date	Arrived late by	Largest filed cause
25 January 2026	6 hours 9 minutes	Extreme weather
2 August 2026	4 hours 36 minutes	Late-arriving aircraft
8 September 2025	2 hours 36 minutes	Carrier
5 December 2025	2 hours 15 minutes	Late-arriving aircraft
29 August 2026	2 hours 11 minutes	Late-arriving aircraft

Delay causes

Why DL 421 runs late

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 5,146 reported delay minutes.

Carrier
39%
Late-arriving aircraft
29%
National Airspace System
21%
Extreme weather
10%
Security
1%

The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,982 of the 5,146 delay minutes reported here. The split is drawn from 5,146 delay minutes reported on DL 421.

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

7.2% 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 roughly 50 minutes, which a normal layover absorbs.

At 1,749 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The same number turns up on one other city pair in the data, including LAS to DTW (98), but none flew often enough under DL 421 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DTW to LAS only.

One caution: this is a thin sample. 361 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 421

For a booking, read DL 421 as 72.4% on time with 0.55% cancelled over 361 flights. Those are rates from the past twelve months, not a forecast for any particular 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures