Flight number record

DL 729

Delta Air Lines · San Diego to Atlanta

Route: SAN → ATL
Departs: 06:15
Flights: 365
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 729, check with Delta Air Lines.

DL 729 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 14 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 55 minutes. That rests on 365 flights, with a median arrival 6 minutes early.

Set against the rest of the country, DL 729's record is 14 points better than the US average of 77.3%. That gap is worth roughly 136 fewer late arrivals for every thousand flights.

On time

90.9%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.82%

National rate is 1.89%

1 hour+ late

1.1%

National rate is 8.3%

These figures cover 365 flights between September 2025 and August 2026. The median arrival is 6 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 729 flies

DL 729 flies SAN to ATL without a single fixed slot. Its most common scheduled departure was 06:15, used on 271 of 365 flights, with 06:30 (62 flights) next.

Departs 06:15271 flights74.2%
Departs 06:3062 flights17.0%

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 06:15 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 729 runs level with that at 90.9%. 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 729 next to SAN to ATL

Every carrier on SAN to ATL combined arrived on time 85.7% of the time across 2,352 flights, so DL 729 is 5 points ahead of it. Delta flew 2,172 flights on the same city pair under all its flight numbers, including this one, and those ran 86.1% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 10 points.

DL 729 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 729	365	90.9%	54 min	0.82%	A+
All Delta Air Lines on SAN–ATL	2,172	86.1%	76 min	0.69%	A+
All carriers on SAN–ATL	2,352	85.7%	74 min	0.64%	A+
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 729 quarter by quarter

DL 729 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Jul–Sep 2026 at 82.3%, a swing of 18 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 flights100.0%
Oct–Dec 202592 flights97.8%
Jan–Mar 202690 flights85.2%
Apr–Jun 202691 flights92.2%
Jul–Sep 202662 flights82.3%

Scale runs 75% to 100%.

By weekday, DL 729 ranged from 86.3% on Saturday to 94.0% on Sunday. With about 52 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late DL 729 runs when it is late

Most of the lateness is short. 21 of the 33 late arrivals were under half an hour behind, and 4 reached an hour or more.

15+ min early80 flights22.2%
Within 15 min248 flights68.7%
15–29 min late21 flights5.8%
30–59 min late8 flights2.2%
1–2 hours late1 flights0.3%
2+ hours late3 flights0.8%

Scale runs 0% to 100%.

Share of 361 completed flights by arrival against schedule.

Only 14 of 361 completed flights left 15 minutes late or more, too few to say how often the time is made up.

The worst days

Worst days for DL 729

The latest arrival of the period was on 19 December 2025, 8 hours 44 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).

The latest arrivals of DL 729 in the period
Date	Arrived late by	Largest filed cause
19 December 2025	8 hours 44 minutes	Late-arriving aircraft
17 January 2026	3 hours 34 minutes	Carrier
27 August 2026	3 hours 34 minutes	Carrier
21 February 2026	1 hour 36 minutes	Carrier
6 July 2026	44 minutes	National Airspace System

Delay causes

Why DL 729 runs late

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 1,780 reported delay minutes.

Carrier
38%
Late-arriving aircraft
29%
National Airspace System
29%
Extreme weather
4%

The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 671 of the 1,780 delay minutes reported here. The split is drawn from 1,780 delay minutes reported on DL 729.

Cancellations are rare at 0.82%, 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

Badly late arrivals are rare here: only 1.1% 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 1,892 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 729 in the data flew SAN to ATL. 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 729

For a booking, DL 729 has one of the better records a US domestic flight can show: 90.9% on time and 0.82% cancelled. That is a base rate, not a promise about any single 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures