Flight number record
DL 734
Delta Air Lines · Detroit to Seattle
- Route
- DTW → SEA
- Departs
- 08:30
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 734, check with Delta Air Lines.
DL 734 sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land roughly 40 minutes behind schedule. That rests on 365 flights, with a median arrival right on schedule.
Key figures
On time
73.9%
Arrivals under 15 minutes late, of 357 completed flights
Avg delay
41 min
Across delayed arrivals only, not all flights
Cancelled
1.64%
National rate is 1.89%
1 hour+ late
3.9%
National rate is 8.3%
These figures cover 365 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 734 flies
DL 734 flies DTW to SEA without a single fixed slot. Its most common scheduled departure was 08:30, used on 147 of 365 flights, with 08:25 (128 flights) and 08:35 (58 flights) next.
- Departs 08:30147 flights40.3%
- Departs 08:25128 flights35.1%
- Departs 08:3558 flights15.9%
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 08:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 734 runs 10 points worse at 73.9%. 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 734 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 734 is about level with 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 7 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 734 | 365 | 73.9% | 41 min | 1.64% | C |
| 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 734 quarter by quarter
DL 734 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jan–Mar 2026 at 67.1%, a swing of 26 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 202592 flights72.2%
- Jan–Mar 202690 flights67.1%
- Apr–Jun 202691 flights76.9%
- Jul–Sep 202662 flights72.1%
Scale runs 60% to 100%.
By weekday, DL 734 did best on Wednesday at 82.7% on time and worst on Tuesday at 63.5%. Each day rests on about 52 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 734 runs when it is late
The 93 late arrivals split 45 under half an hour, 34 between 30 and 60 minutes, and 14 an hour or more.
- 15+ min early78 flights21.8%
- Within 15 min186 flights52.1%
- 15–29 min late45 flights12.6%
- 30–59 min late34 flights9.5%
- 1–2 hours late8 flights2.2%
- 2+ hours late6 flights1.7%
Scale runs 0% to 100%.
Share of 357 completed flights by arrival against schedule.
12 of 54 late departures made up the time and arrived on time, 22% of them. In the other direction, 51 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 734
The latest arrival of the period was on 6 January 2026, 2 hours 53 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 January 2026 | 2 hours 53 minutes | Carrier |
| 23 January 2026 | 2 hours 39 minutes | Carrier |
| 5 December 2025 | 2 hours 35 minutes | Carrier |
| 25 January 2026 | 2 hours 35 minutes | Carrier |
| 6 September 2025 | 2 hours 20 minutes | Carrier |
Delay causes
Why DL 734 runs late
Carrier accounts for 49% of the 3,824 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Carrier
- 42%National Airspace System
- 6%Late-arriving aircraft
- 3%Extreme weather
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,859 of the 3,824 delay minutes reported here. The split is drawn from 3,824 delay minutes reported on DL 734.
Cancellations sit at 1.64% against a national 1.89%, which is ordinary. Diversions add another 0.55%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.9% 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.
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 365 flights under DL 734 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. 365 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 734
For a booking, read DL 734 as 73.9% on time with 1.64% cancelled over 365 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 728 on the same route76.7%
- 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.