1,851 nonstop flights · Aug 2025 – Jul 2026 · US DOT on-time records, all US airlines

No clear winner: airlines and hours on this route all land within a few points of 4 in 5 on time.

Best time to leave 6–7 am 92% arrive on time from IAD

Best single flight AS 351 IAD 06:00 → SEA 08:46 · 79% on time Avoid UA 326 IAD 17:55 → SEA 20:46 · 77% 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).

IAD

% 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.

Airlines on this route

Arriving within 15 minutes. Regional flights count under the airline that sells them. Pick an airline to see its flights.


United	655	81%	0.6%	62 min
Delta	361	78%	1.4%	98 min
Alaska	835	76%	1.2%	50 min

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.


AS 351	IAD 06:00	SEA 08:46	79%
DL 1015	IAD 07:00	SEA 09:45	79%
UA 326	IAD 17:55	SEA 20:46	77%

All 9 flights on this route →

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.


United	IAD	SEA	5h 51m	81%	0.6%	655	Flying now
Delta	IAD	SEA	5h 57m	78%	1.4%	361	Flying now
Alaska	IAD	SEA	5h 46m	76%	1.2%	835	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