Flight number record

DL 429

Delta Air Lines · Seattle to New York

Route: SEA → JFK
Departs: 07:20
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 10 points better than the national rate of 77.6%. 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 10 points better than the US average of 77.6%. That gap is worth roughly 103 fewer late arrivals for every thousand flights.

On time

87.9%

Arrivals under 15 minutes late, of 346 completed flights

Avg delay

111 min

Across delayed arrivals only, not all flights

Cancelled

3.29%

National rate is 1.81%

1 hour+ late

4.3%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 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.

Schedule

When DL 429 flies

DL 429 flies SEA to JFK without a single fixed slot. Its most common scheduled departure was 07:20, used on 107 of 365 flights, with 07:15 (90 flights) and 07:10 (78 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:20107 flights29.3%
Departs 07:1590 flights24.7%
Departs 07:1078 flights21.4%

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 07:20 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 87.9%. 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 429 next to SEA to JFK

Every carrier on SEA to JFK combined arrived on time 75.3% of the time across 2,906 flights, so DL 429 is 13 points ahead of it. Delta flew 1,337 flights on the same city pair under all its flight numbers, including this one, and those ran 79.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 6 points.

DL 429 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 429	365	87.9%	111 min	3.29%	A−
All Delta Air Lines on SEA–JFK	1,337	79.6%	70 min	2.39%	B
All carriers on SEA–JFK	2,906	75.3%	62 min	2.41%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 429 quarter by quarter

Quarter by quarter DL 429 held fairly steady: 91.0% in Jul–Sep 2025, 86.2% in Oct–Dec 2025, 82.9% in Jan–Mar 2026 and 90.9% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights91.0%
Oct–Dec 202592 flights86.2%
Jan–Mar 202690 flights82.9%
Apr–Jun 202691 flights90.9%

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

By weekday, DL 429 ranged from 83.7% on Sunday to 94.1% on Wednesday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why DL 429 runs late

One category carries most of the weight here. Carrier accounts for 61% of the 4,674 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
61%
National Airspace System
21%
Late-arriving aircraft
10%
Extreme weather
8%

The largest share of delay minutes, 61%, 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 2,873 of the 4,674 delay minutes reported here. The split is drawn from 4,674 delay minutes reported on DL 429.

Cancellations run at 3.29%, against 1.81% nationally. That is about one flight in 30 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 4.3% 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 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: 3.29% 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures