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 → ORD
Dulles to Chicago: 2,024 nonstop flights a year
On time (12 months)
75%
Cancelled
0.8%
avg delay 19 min
Best time to leave
Before 9 AM
88% on time vs 40% 6 to 9 PM
Most reliable airline
United
74% chance on time
Lowest nonstop fare seen in the next two months: $147 (United 565 on 2026-11-17). 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 1778
6:15 AM → 7:26 AM2h 11m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 279; its record covers all of them.
89%
chance on time
- On time (history)
- 91%
- Cancelled
- 1.2%
- Avg arrival delay
- 5 min
- Arrived on time 91% of the time (80 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 6 to 9 PM: 40%).
- 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 · 80 flights
Find United 1778 fares Opens this date on Aviasales#2 · United 1252
10:10 AM → 11:27 AM2h 18m nonstop
Local times, typical schedule. Last flown 2026-05-31.
85%
chance on time
- On time (history)
- 89%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 89% of the time (64 flights, Jun 2025 to May 2026).
- Never cancelled in 64 scheduled flights.
- 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 · 64 flights
Find United 1252 fares Opens this date on Aviasales#3 · United 1775
8:20 AM → 9:38 AM2h 18m nonstop
Local times, typical schedule. Last flown 2026-05-31.
81%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.4%
- Avg arrival delay
- 8 min
- Arrived on time 82% of the time (248 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 6 to 9 PM: 40%).
- 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 · 248 flights
Find United 1775 fares Opens this date on Aviasales#4 · United 2331
1:10 PM → 2:27 PM2h 18m nonstop
Local times, typical schedule. Last flown 2026-05-31.
80%
chance on time
- On time (history)
- 81%
- Cancelled
- 0.8%
- Avg arrival delay
- 17 min
- Arrived on time 81% of the time (361 flights, Jun 2025 to May 2026).
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 361 flights
Find United 2331 fares Opens this date on Aviasales#5 · United 1738
10:30 PM → 11:44 PM2h 13m nonstop
Local times, typical schedule. Last flown 2026-05-31.
78%
chance on time
- On time (history)
- 79%
- Cancelled
- 1.4%
- Avg arrival delay
- 16 min
- Arrived on time 79% of the time (355 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 · 355 flights
Find United 1738 fares Opens this date on Aviasales#6 · United 2649
3:15 PM → 4:30 PM2h 15m nonstop
Local times, typical schedule. Last flown 2026-05-31.
67%
chance on time
- On time (history)
- 66%
- Cancelled
- 0.0%
- Avg arrival delay
- 29 min
- Arrived on time 66% of the time (32 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 ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 32 flights
Find United 2649 fares Opens this date on Aviasales#7 · United 2497
5:26 PM → 6:44 PM2h 18m nonstop
Local times, typical schedule. Last flown 2026-05-31.
47%
chance on time
- On time (history)
- 47%
- Cancelled
- 1.1%
- Avg arrival delay
- 42 min
- Arrived on time 47% of the time (359 flights, Jun 2025 to May 2026).
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 359 flights
Find United 2497 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines74%
2,024 flights · 75% on time as flown · 0.8% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM88%
655 flights · avg delay 6 min
- 9 AM to noon88%
66 flights · avg delay 8 min
- Noon to 3 PM81%
365 flights · avg delay 17 min
- 3 to 6 PM53%
508 flights · avg delay 39 min
- 6 to 9 PM40%
67 flights · avg delay 31 min
- After 9 PM79%
363 flights · avg delay 16 min
Best day: Tuesday (81%). Worst: Friday (76%).
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