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Ranking & search details
7 nonstop, 33 with 1 connection, 6 with 2 · ranked by overall best · 10 hidden by your Most reliable time setting (they leave at other times of day) · showing the top 3
Most reliable time: morning departures (5–11 AM), the window with the best on-time odds for this trip. Turn off “Most reliable” under Departure time in Advanced settings to see every time.
Fares seen on this date: nonstop from 208 (recent searches, one way, per person; each card opens the live price)
36 matching trips
Why this is our top pick
- This morning flight leaves in the most reliable time of day on this route: its best departures have a 79% reliability rating vs 68% for afternoon departures.
- United trips we compared arrive on time 80% of the time on average, 2 points more often than Delta, Alaska and American (78%).
- Compared with the next-best option (Delta 1015 on the Airbus A220-300), it arrives on time 6 points more often.
- Legroom was comparable across the flights we compared (30–31 in), so it didn't set them apart.
Aircraft and legroom reflect the planes each flight has flown recently. Airlines can swap planes and seat maps change, so check the airline’s seat map when you book.
IAD → SEA
Dulles to Seattle: 1,926 nonstop flights a year
On time (12 months)
76%
Cancelled
1.0%
avg delay 16 min
Best time to leave
Noon to 3 PM
93% on time vs 59% 6 to 9 PM
Most reliable airline
United
78% chance on time
Lowest nonstop fare seen in the next two months: $208 (Alaska 737 on 2026-11-25). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines78%
730 flights · 79% on time as flown · 0.6% cancel
- Delta Air Lines76%
361 flights · 77% on time as flown · 1.5% cancel
- Alaska Airlines71%
835 flights · 72% on time as flown · 1.1% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM80%
754 flights · avg delay 16 min
- 9 AM to noon79%
246 flights · avg delay 11 min
- Noon to 3 PM93%
165 flights · avg delay 7 min
- 3 to 6 PM72%
381 flights · avg delay 18 min
- 6 to 9 PM59%
303 flights · avg delay 25 min
- After 9 PM70%
77 flights · avg delay 15 min
Best day: Wednesday (82%). Worst: Monday (77%).
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure