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.
OAK → MDW
Oakland to Chicago: 459 nonstop flights a year
On time (12 months)
88%
Cancelled
0.2%
avg delay 5 min
Best time to leave
Before 9 AM
91% on time vs 84% noon to 3 PM
Most reliable airline
Southwest
88% chance on time
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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 · Southwest 3551
5:55 AM → 12:00 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-29.
90%
chance on time
- On time (history)
- 90%
- Cancelled
- 0.0%
- Avg arrival delay
- 5 min
- Arrived on time 90% of the time (39 flights, Jun 2025 to May 2026).
- Never cancelled in 39 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 91% on time; Noon to 3 PM: 84%).
- Lands inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
Limited track record · 39 flights
Find Southwest 3551 fares Opens this date on Aviasales#2 · Southwest 1150
5:45 AM → 11:45 AM4h 00m nonstop
Local times, typical schedule. Last flown 2026-04-06.
87%
chance on time
- On time (history)
- 85%
- Cancelled
- 3.6%
- Avg arrival delay
- 7 min
- Arrived on time 85% of the time (26 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 91% on time; Noon to 3 PM: 84%).
- Lands inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- Short track record (26 flights), so its score leans on the airline's record at this hour.
Limited track record · 26 flights
Find Southwest 1150 fares Opens this date on Aviasales#3 · Southwest 3552
11:55 PM → 6:00 AM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 4069; its record covers all of them.
87%
chance on time
- On time (history)
- 86%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 86% of the time (87 flights, Jun 2025 to May 2026).
- Never cancelled in 87 scheduled flights.
Moderate track record · 87 flights
Find Southwest 3552 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines88%
459 flights · 88% on time as flown · 0.2% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM91%
241 flights · avg delay 4 min
- 9 AM to noon85%
88 flights · avg delay 6 min
- Noon to 3 PM84%
33 flights · avg delay 11 min
- After 9 PM86%
88 flights · avg delay 6 min
Best day: Saturday (86%). Worst: Monday (76%).
Smarter routing
Nearby airports that run more on time
SJC → ORD 91% chance on time
Norman Y. Mineta San Jose International Airport to Chicago O'Hare International Airport · 301 flights a year · 44 mi from your airports · yours: 88%
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