Flight number record

DL 779

Delta Air Lines · Atlanta to Ontario

Route: ATL → ONT
Departs: 20:59
Flights: 251
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 779, check with Delta Air Lines.

DL 779 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 251 flights, with a median arrival 2 minutes late.

The national on-time rate over the same period is 77.6%, so DL 779 runs 9 points behind the country as a whole. Across a thousand flights that is about 92 extra late arrivals.

On time

68.4%

Arrivals under 15 minutes late, of 247 completed flights

Avg delay

62 min

Across delayed arrivals only, not all flights

Cancelled

1.20%

National rate is 1.81%

1 hour+ late

10.1%

National rate is 8.1%

These figures cover 251 flights between July 2025 and June 2026. Beyond the headline rate, 10.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Schedule

When DL 779 flies

DL 779 flies ATL to ONT without a single fixed slot. Its most common scheduled departure was 20:59, used on 38 of 251 flights, with 19:18 (38 flights) and 21:20 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 20:5938 flights15.1%
Departs 19:1838 flights15.1%
Departs 21:2035 flights13.9%

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 20:59 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 779 runs 2 points worse at 68.4%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 779 next to ATL to ONT

Every carrier on ATL to ONT combined arrived on time 76.6% of the time across 937 flights, so DL 779 is 8 points behind it. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 13 points.

DL 779 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 779thin sample	251	68.4%	62 min	1.20%	C
All Delta Air Lines on ATL–ONT	937	76.6%	55 min	1.71%	B
All carriers on ATL–ONT	937	76.6%	55 min	1.71%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 779 quarter by quarter

DL 779 did not run the same all year. Its best quarter was Apr–Jun 2026 at 76.1% on time and its weakest Jul–Sep 2025 at 58.5%, a swing of 18 points on roughly 63 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 202565 flights58.5%
Oct–Dec 202577 flights68.4%
Jan–Mar 202640 flights71.8%
Apr–Jun 202669 flights76.1%

Scale runs 50% to 80%. Rows with fewer than 30 flights show a dash.

By weekday, DL 779 did best on Friday at 79.5% on time and worst on Monday at 50.0%. Each day rests on about 36 flights, so a gap of 30 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 779 runs late

One category carries most of the weight here. Carrier accounts for 55% of the 4,827 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
55%
Late-arriving aircraft
26%
National Airspace System
14%
Extreme weather
6%

The largest share of delay minutes, 55%, 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 2,654 of the 4,827 delay minutes reported here. The split is drawn from 4,827 delay minutes reported on DL 779.

Cancellations sit at 1.20% against a national 1.81%, which is ordinary. Diversions add another 0.40%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.1% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 1,900 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.

The same number turns up on one other city pair in the data, including DCA to SEA (24), but none flew often enough under DL 779 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to ONT only.

One caution: this is a thin sample. 251 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 779

For a booking, DL 779 is one of the weaker ways to fly ATL to ONT: 8 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

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