ATIS Alerts Smart Flight Search
Find the flight least likely to be delayed
BetaWe rank real flight numbers by how often they flew and arrived on time over the last 12 months, adjusted for your travel month and departure time, then check nearby airports and calmer connections. US airlines and airports.
IAD → DEN
Dulles to Denver: 3,624 nonstop flights a year
On time (12 months)
81%
Cancelled
0.7%
avg delay 14 min
Best time to leave
9 AM to noon
91% on time vs 62% 6 to 9 PM
Most reliable airline
United
82% chance on time
Lowest nonstop fare seen in the next two months: $303 (United 495 on 2026-11-02). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · United 1865
9:55 AM → 12:00 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
93%
chance on time
- On time (history)
- 95%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 95% of the time (86 flights, Jun 2025 to May 2026).
- Never cancelled in 88 scheduled flights.
- Leaves in this route's most on-time window (9 AM to noon: 91% on time; 6 to 9 PM: 62%).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Moderate track record · 86 flights
Find United 1865 fares Opens this date on Aviasales#2 · United 2035
6:30 AM → 8:22 AM3h 52m nonstop
Local times, typical schedule. Last flown 2026-05-31.
91%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 0 min
- Arrived on time 100% of the time (11 flights, Jun 2025 to May 2026).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
- Short track record (11 flights), so its score leans on the airline's record at this hour.
Limited track record · 11 flights
Find United 2035 fares Opens this date on Aviasales#3 · United 1587
12:43 PM → 2:48 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
91%
chance on time
- On time (history)
- 92%
- Cancelled
- 0.3%
- Avg arrival delay
- 8 min
- Arrived on time 92% of the time (288 flights, Jun 2025 to May 2026).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 288 flights
Find United 1587 fares Opens this date on Aviasales#4 · United 644
8:25 AM → 10:28 AM4h 03m nonstop
Local times, typical schedule. Last flown 2026-05-20. Same departure also flew as United 1256; its record covers all of them.
88%
chance on time
- On time (history)
- 92%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 92% of the time (52 flights, Jun 2025 to May 2026).
- Never cancelled in 53 scheduled flights.
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
- Short track record (52 flights), so its score leans on the airline's record at this hour.
Limited track record · 52 flights
Find United 644 fares Opens this date on Aviasales#5 · United 2768
8:15 AM → 10:10 AM3h 55m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 2357; its record covers all of them.
87%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 91% of the time (35 flights, Jun 2025 to May 2026).
- Never cancelled in 35 scheduled flights.
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
- Short track record (35 flights), so its score leans on the airline's record at this hour.
Limited track record · 35 flights
Find United 2768 fares Opens this date on Aviasales#6 · United 1126
2:37 PM → 4:45 PM4h 08m nonstop
Local times, typical schedule. Last flown 2026-05-31.
85%
chance on time
- On time (history)
- 90%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 90% of the time (31 flights, Jun 2025 to May 2026).
- Never cancelled in 32 scheduled flights.
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 31 flights
Find United 1126 fares Opens this date on Aviasales#7 · Southwest 2439
5:55 AM → 7:45 AM3h 50m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 3339; its record covers all of them.
85%
chance on time
- On time (history)
- 89%
- Cancelled
- 1.1%
- Avg arrival delay
- 5 min
- Arrived on time 89% of the time (87 flights, Jun 2025 to May 2026).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Moderate track record · 87 flights
Find Southwest 2439 fares Opens this date on Aviasales#8 · United 495
10:35 PM → 12:44 AM4h 09m nonstop
Local times, typical schedule. Last flown 2026-05-31.
82%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.6%
- Avg arrival delay
- 14 min
- Arrived on time 82% of the time (308 flights, Jun 2025 to May 2026).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Strong track record · 308 flights
Find United 495 fares Opens this date on Aviasales#9 · United 395
4:00 PM → 6:10 PM4h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
82%
chance on time
- On time (history)
- 85%
- Cancelled
- 0.0%
- Avg arrival delay
- 11 min
- Arrived on time 85% of the time (88 flights, Jun 2025 to May 2026).
- Never cancelled in 88 scheduled flights.
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Moderate track record · 88 flights
Find United 395 fares Opens this date on Aviasales#10 · United 431
2:21 PM → 4:28 PM4h 07m nonstop
Local times, typical schedule. Last flown 2026-04-29.
82%
chance on time
- On time (history)
- 84%
- Cancelled
- 0.0%
- Avg arrival delay
- 10 min
- Arrived on time 84% of the time (55 flights, Jun 2025 to May 2026).
- Never cancelled in 56 scheduled flights.
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 55 flights
Find United 431 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines82%
2,787 flights · 83% on time as flown · 0.5% cancel
- Southwest Airlines75%
837 flights · 75% on time as flown · 1.2% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM89%
804 flights · avg delay 9 min
- 9 AM to noon91%
394 flights · avg delay 6 min
- Noon to 3 PM86%
833 flights · avg delay 11 min
- 3 to 6 PM72%
885 flights · avg delay 20 min
- 6 to 9 PM62%
367 flights · avg delay 23 min
- After 9 PM83%
341 flights · avg delay 13 min
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