Flight number record
DL 728
Delta Air Lines · Detroit to Seattle
- Route
- DTW → SEA
- Departs
- 12:20
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 728, check with Delta Air Lines.
DL 728 lands a B+, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 364 flights, with a median arrival 4 minutes early.
Key figures
On time
76.7%
Arrivals under 15 minutes late, of 361 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
5.5%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 4 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 728 flies
DL 728 flies DTW to SEA without a single fixed slot. Its most common scheduled departure was 12:20, used on 98 of 364 flights, with 12:43 (40 flights) next.
- Departs 12:2098 flights26.9%
- Departs 12:4340 flights11.0%
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 12:20 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 728 runs level with that at 76.7%. 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 728 next to DTW to SEA
Every carrier on DTW to SEA combined arrived on time 72.8% of the time across 2,067 flights, so DL 728 is 4 points ahead of it. Delta flew 1,518 flights on the same city pair under all its flight numbers, including this one, and those ran 71.3% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 728thin sample | 364 | 76.7% | 50 min | 0.55% | B+ |
| All Delta Air Lines on DTW–SEA | 1,518 | 71.3% | 57 min | 0.79% | C+ |
| All carriers on DTW–SEA | 2,067 | 72.8% | 56 min | 0.68% | C+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 728 quarter by quarter
DL 728 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Oct–Dec 2025 at 63.7%, a swing of 30 points on roughly 73 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 flights93.3%
- Oct–Dec 202591 flights63.7%
- Jan–Mar 202690 flights70.1%
- Apr–Jun 202691 flights87.9%
- Jul–Sep 202662 flights80.6%
Scale runs 55% to 100%.
By weekday, DL 728 did best on Tuesday at 82.7% on time and worst on Monday at 67.9%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 728 runs when it is late
DL 728 often beats the schedule: 93 of 361 completed flights, 26%, arrived 15 minutes or more early. The 84 late arrivals split 39 under half an hour, 25 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early93 flights25.8%
- Within 15 min184 flights51.0%
- 15–29 min late39 flights10.8%
- 30–59 min late25 flights6.9%
- 1–2 hours late14 flights3.9%
- 2+ hours late6 flights1.7%
Scale runs 0% to 100%.
Share of 361 completed flights by arrival against schedule.
8 of 57 late departures made up the time and arrived on time, 14% of them. In the other direction, 35 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 SEA.
The worst days
Worst days for DL 728
The latest arrival of the period was on 17 March 2026, 4 hours 58 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 17 March 2026 | 4 hours 58 minutes | National Airspace System |
| 14 June 2026 | 4 hours 1 minute | Carrier |
| 1 November 2025 | 3 hours 20 minutes | Carrier |
| 14 December 2025 | 2 hours 55 minutes | Late-arriving aircraft |
| 19 February 2026 | 2 hours 19 minutes | Carrier |
Delay causes
Why DL 728 runs late
Carrier accounts for 47% of the 4,178 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Carrier
- 32%National Airspace System
- 20%Late-arriving aircraft
- 1%Extreme weather
32% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,349 minutes out of 4,178, against a national NAS share of 21%. The split is drawn from 4,178 delay minutes reported on DL 728.
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
5.5% 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 about 50 minutes, which a normal layover absorbs.
At 1,927 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.
Every one of the 364 flights under DL 728 in the data flew DTW to SEA. 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 728
For a booking, read DL 728 as 76.7% on time with 0.55% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DTW to SEA, every carrier and departure
- SEA to DTW, the return direction
- Delta Air Lines 734 on the same route73.9%
- Delta Air Lines 565 on the same route61.6%
- Alaska Airlines 313 on the same route75.1%
- Delta Air Lines 944 on the same route67.3%
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Seattle-Tacoma International (SEA) 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.