Showing Delta only (incl. its regional partners)All airlines ×

1,076 nonstop flights · Aug 2025 – Jul 2026 · US DOT on-time records, all US airlines

No clear winner: Delta’s ONT → SEA flights land within a few points of 92% on time whatever the hour.

Best time to leave 3–4 pm 97% arrive on time from ONT

Best single flight DL 4070 ONT 11:59 → SEA 14:53 · 91% on time Avoid DL 4031 ONT 17:59 → SEA 20:50 · 90% on time

Time of day × airport

Share of this route’s flights leaving within 15 minutes, by airport and scheduled departure hour, over Aug 2025 – Jul 2026. Blank: no flights then (or fewer than 40 in the year).

ONT

% of this route’s flights leaving within 15 min (small number: flights in the Jun 6 – Jul 31, 2026 schedule): 85+75–8465–7455–64under 55

Pick an hour to see this route’s flights leaving then.

Flights, best and worst

Flights in the Jun 6 – Jul 31, 2026 schedule that ran 150+ times in the year. Times are local. Pick a flight for its history.


DL 4070flown by SkyWest	ONT 11:59	SEA 14:53	91%
DL 4031flown by SkyWest	ONT 17:59	SEA 20:50	90%

All 4 Delta flights in the current schedule

Every flight that flew in the Jun 6 – Jul 31, 2026 schedule, with its record over Aug 2025 – Jul 2026. Times are local. Click a column to sort.


DL 3816flown by SkyWest	ONT 06:20	SEA 09:17	2h 57m	86	94%	0.0%	81 min
DL 4070flown by SkyWest	ONT 11:59	SEA 14:53	3h 01m	151	91%	0.0%	158 min
DL 3840flown by SkyWest	ONT 13:35	SEA 16:33	2h 58m	31	90%	0.0%	27 min
DL 4031flown by SkyWest	ONT 17:59	SEA 20:50	2h 51m	322	90%	0.3%	70 min

Nonstops by airline and airport

Arriving within 15 minutes, Aug 2025 – Jul 2026. Pick a row to see that airline’s flights on that airport pair.


Delta	ONT	SEA	2h 58m	92%	0.3%	1,076	Flying now

Flying on a particular day? Pick a date above and the same ranking uses our forecast odds for each flight that day: Tomorrow.

About this data: US DOT on-time records, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. Schedules (which flights and connections exist, and their times) are as of Jun 6 – Jul 31, 2026; seasonal flights outside that window aren’t ranked. Rebuilt monthly. JSON