Flight number record

DL 2721

Delta Air Lines · San Francisco to Seattle

Route: SFO → SEA
Departs: 05:55
Flights: 349
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 2721, check with Delta Air Lines.

DL 2721 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 19 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 349 flights, with a median arrival 21 minutes early.

Set against the rest of the country, DL 2721's record is 19 points better than the US average of 77.6%. That gap is worth roughly 186 fewer late arrivals for every thousand flights.

On time

96.2%

Arrivals under 15 minutes late, of 346 completed flights

Avg delay

69 min

Across delayed arrivals only, not all flights

Cancelled

0.86%

National rate is 1.81%

1 hour+ late

1.7%

National rate is 8.1%

These figures cover 349 flights between July 2025 and June 2026. The median arrival is 21 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 2721 flies

DL 2721 flies SFO to SEA without a single fixed slot. Its most common scheduled departure was 05:55, used on 175 of 349 flights, with 06:00 (134 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 05:55175 flights50.1%
Departs 06:00134 flights38.4%

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 05:55 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 2721 runs 7 points better at 96.2%. 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 2721 next to SFO to SEA

Every carrier on SFO to SEA combined arrived on time 73.7% of the time across 6,770 flights, so DL 2721 is 23 points ahead of it. Delta flew 924 flights on the same city pair under all its flight numbers, including this one, and those ran 83.6% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 15 points.

DL 2721 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 2721thin sample	349	96.2%	69 min	0.86%	A+
All Delta Air Lines on SFO–SEA	924	83.6%	74 min	1.73%	B
All carriers on SFO–SEA	6,770	73.7%	56 min	1.18%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 2721 quarter by quarter

Quarter by quarter DL 2721 held fairly steady: 97.8% in Jul–Sep 2025, 95.0% in Oct–Dec 2025, 95.2% in Jan–Mar 2026 and 96.7% in Apr–Jun 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights97.8%
Oct–Dec 202580 flights95.0%
Jan–Mar 202686 flights95.2%
Apr–Jun 202691 flights96.7%

Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 2721 ranged from 92.2% on Tuesday to 100.0% on Monday. With about 50 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.

Delay causes

Why DL 2721 runs late

One category carries most of the weight here. Carrier accounts for 69% of the 899 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
69%
Late-arriving aircraft
25%
National Airspace System
7%

The largest share of delay minutes, 69%, 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 619 of the 899 delay minutes reported here. The split is drawn from 899 delay minutes reported on DL 2721.

Cancellations are rare at 0.86%, below the national 1.81% 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 1.7% 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.

The 679 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The same number turns up on one other city pair in the data, including BNA to DTW (9), but none flew often enough under DL 2721 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SFO to SEA only.

One caution: this is a thin sample. 349 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 2721

For a booking, DL 2721 has one of the better records a US domestic flight can show: 96.2% on time and 0.86% 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures