Flight number record

DL 721

Delta Air Lines · Santa Ana to Atlanta

Route: SNA → ATL
Departs: 06:45
Flights: 365
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 721, check with Delta Air Lines.

DL 721 lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 365 flights, with a median arrival 3 minutes early.

On time

80.2%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

89 min

Across delayed arrivals only, not all flights

Cancelled

0.82%

National rate is 1.89%

1 hour+ late

7.3%

National rate is 8.3%

These figures cover 365 flights between September 2025 and August 2026. The median arrival is 3 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 721 flies

DL 721 is scheduled to leave Santa Ana (SNA) at 06:45 local time and reach Atlanta (ATL) at 13:53. That slot held for 313 of the 365 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.

Departs 06:45313 flights85.8%
Departs 07:4546 flights12.6%

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 06:45 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 721 runs 9 points worse at 80.2%. 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 721 next to SNA to ATL

Every carrier on SNA to ATL combined arrived on time 79.9% of the time across 1,020 flights, so DL 721 is about level with it. Across its whole network Delta Air Lines managed 81.1%, close to this flight's figure.

DL 721 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 721	365	80.2%	89 min	0.82%	B+
All Delta Air Lines on SNA–ATL	1,020	79.9%	98 min	0.98%	B+
All carriers on SNA–ATL	1,020	79.9%	98 min	0.98%	B+
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 721 quarter by quarter

DL 721 did not run the same all year. Its best quarter was Apr–Jun 2026 at 85.7% on time and its weakest Jul–Sep 2026 at 74.1%, a swing of 12 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 202530 flights—
Oct–Dec 202592 flights82.4%
Jan–Mar 202690 flights75.3%
Apr–Jun 202691 flights85.7%
Jul–Sep 202662 flights74.1%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 721 did best on Thursday at 90.4% on time and worst on Sunday at 66.7%. Each day rests on about 52 flights, so a gap of 24 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late DL 721 runs when it is late

The 71 late arrivals split 34 under half an hour, 11 between 30 and 60 minutes, and 26 an hour or more.

15+ min early49 flights13.7%
Within 15 min238 flights66.5%
15–29 min late34 flights9.5%
30–59 min late11 flights3.1%
1–2 hours late8 flights2.2%
2+ hours late18 flights5.0%

Scale runs 0% to 100%.

Share of 358 completed flights by arrival against schedule.

9 of 54 late departures made up the time and arrived on time, 17% of them. In the other direction, 26 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 ATL.

The worst days

Worst days for DL 721

The latest arrival of the period was on 22 December 2025, 11 hours 57 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.

The latest arrivals of DL 721 in the period
Date	Arrived late by	Largest filed cause
22 December 2025	11 hours 57 minutes	Carrier
1 June 2026	7 hours 47 minutes	Carrier
29 September 2025	7 hours 11 minutes	Carrier
5 May 2026	5 hours 22 minutes	Late-arriving aircraft
20 January 2026	5 hours 15 minutes	Carrier

Delay causes

Why DL 721 runs late

Carrier accounts for 62% of the 6,348 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
62%
National Airspace System
19%
Late-arriving aircraft
17%
Extreme weather
2%

The largest share of delay minutes, 62%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,908 of the 6,348 delay minutes reported here. The split is drawn from 6,348 delay minutes reported on DL 721.

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

7.3% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.

At 1,919 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 721 in the data flew SNA 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 721

For a booking, read DL 721 as 80.2% on time with 0.82% 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures