Flight number record

DL 429

Delta Air Lines · Seattle to New York

Route: SEA → JFK
Departs: 07:15
Flights: 365
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 429, check with Delta Air Lines.

DL 429 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 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 10 minutes early.

Set against the rest of the country, DL 429's record is 11 points better than the US average of 77.3%. That gap is worth roughly 111 fewer late arrivals for every thousand flights.

On time

88.4%

Arrivals under 15 minutes late, of 344 completed flights

Avg delay

114 min

Across delayed arrivals only, not all flights

Cancelled

4.11%

National rate is 1.89%

1 hour+ late

4.7%

National rate is 8.3%

These figures cover 365 flights between September 2025 and August 2026. The median arrival is 10 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 429 flies

DL 429 flies SEA to JFK without a single fixed slot. Its most common scheduled departure was 07:15, used on 113 of 365 flights, with 07:20 (101 flights) and 07:10 (78 flights) next.

Departs 07:15113 flights31.0%
Departs 07:20101 flights27.7%
Departs 07:1078 flights21.4%

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 07:15 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 429 runs level with that at 88.4%. 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 429 next to SEA to JFK

Every carrier on SEA to JFK combined arrived on time 78.0% of the time across 2,906 flights, so DL 429 is 10 points ahead of it. Delta flew 1,338 flights on the same city pair under all its flight numbers, including this one, and those ran 79.3% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 7 points.

DL 429 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 429	365	88.4%	114 min	4.11%	A−
All Delta Air Lines on SEA–JFK	1,338	79.3%	70 min	3.21%	B−
All carriers on SEA–JFK	2,906	78.0%	69 min	3.20%	B−
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 429 quarter by quarter

Quarter by quarter DL 429 held fairly steady: 86.2% in Oct–Dec 2025, 82.9% in Jan–Mar 2026, 90.9% in Apr–Jun 2026 and 91.4% in Jul–Sep 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202530 flights—
Oct–Dec 202592 flights86.2%
Jan–Mar 202690 flights82.9%
Apr–Jun 202691 flights90.9%
Jul–Sep 202662 flights91.4%

Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 429 did best on Wednesday at 96.1% on time and worst on Sunday at 81.6%. 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 429 runs when it is late

DL 429 often beats the schedule: 116 of 344 completed flights, 34%, arrived 15 minutes or more early. The 40 late arrivals split 15 under half an hour, 9 between 30 and 60 minutes, and 16 an hour or more.

15+ min early116 flights33.7%
Within 15 min188 flights54.7%
15–29 min late15 flights4.4%
30–59 min late9 flights2.6%
1–2 hours late6 flights1.7%
2+ hours late10 flights2.9%

Scale runs 0% to 100%.

Share of 344 completed flights by arrival against schedule.

A late pushback is often recovered here: of 28 departures that left 15 minutes late or more, 10 still arrived on time. In the other direction, 22 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 JFK.

The worst days

Worst days for DL 429

The latest arrival of the period was on 30 May 2026, 11 hours 19 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.

The latest arrivals of DL 429 in the period
Date	Arrived late by	Largest filed cause
30 May 2026	11 hours 19 minutes	Carrier
7 May 2026	9 hours 27 minutes	Carrier
19 April 2026	8 hours 33 minutes	Carrier
23 December 2025	8 hours 4 minutes	Late-arriving aircraft
13 March 2026	6 hours 38 minutes	Extreme weather

Delay causes

Why DL 429 runs late

Carrier accounts for 56% of the 4,563 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
56%
National Airspace System
25%
Late-arriving aircraft
11%
Extreme weather
8%

The largest share of delay minutes, 56%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,577 of the 4,563 delay minutes reported here. The split is drawn from 4,563 delay minutes reported on DL 429.

Cancellations run at 4.11%, against 1.89% nationally. That is about one flight in 25 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 4.7% 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 2,422 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 429 in the data flew SEA to JFK. 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 429

For a booking, the cancellation rate is the figure to plan around on DL 429: 4.11% of its 365 scheduled flights did not operate. A late arrival costs close to two hours, but a cancellation costs the day, so leave a later option open.

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