Flight number record

DL 734

Delta Air Lines · Detroit to Seattle

Route: DTW → SEA
Departs: 08:30
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 734, check with Delta Air Lines.

DL 734 lands a B, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 365 flights, with a median arrival 4 minutes early.

On time

77.7%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

42 min

Across delayed arrivals only, not all flights

Cancelled

1.37%

National rate is 1.81%

1 hour+ late

4.2%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 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.

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 171 of 365 flights, with 08:25 (131 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:30171 flights46.8%
Departs 08:25131 flights35.9%

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 08:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 734 runs 6 points worse at 77.7%. 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 734 next to DTW to SEA

Every carrier on DTW to SEA combined arrived on time 73.2% of the time across 2,076 flights, so DL 734 is 5 points ahead of it. Delta flew 1,535 flights on the same city pair under all its flight numbers, including this one, and those ran 72.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 4 points.

DL 734 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 734	365	77.7%	42 min	1.37%	B
All Delta Air Lines on DTW–SEA	1,535	72.6%	55 min	1.04%	C
All carriers on DTW–SEA	2,076	73.2%	54 min	0.87%	C+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 93.5% on time and its weakest Jan–Mar 2026 at 67.1%, a swing of 26 points on roughly 91 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 202592 flights93.5%
Oct–Dec 202592 flights72.2%
Jan–Mar 202690 flights67.1%
Apr–Jun 202691 flights76.9%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 734 did best on Thursday at 86.5% on time and worst on Tuesday at 69.8%. Each day rests on about 52 flights, so a gap of 17 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 734 runs late

One category carries most of the weight here. Carrier accounts for 49% of the 3,390 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
49%
National Airspace System
45%
Late-arriving aircraft
4%
Extreme weather
2%

The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,646 of the 3,390 delay minutes reported here. The split is drawn from 3,390 delay minutes reported on DL 734.

Cancellations sit at 1.37% against a national 1.81%, 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 4.2% 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.

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 77.7% on time with 1.37% cancelled over 365 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures