Is UA5921 delayed?
No delay reported — UA5921 is expected in San Francisco at 17:50 on Sep 29, as scheduled. Over its last 5 recorded arrivals, 0 landed more than 15 min late.
On time
This update may be out of date. Check with your airline.
Update time unavailable
Departure
Ontario
ONT
Scheduled
Not available
Arrival
San Francisco
SFO
Estimated
Sep 29
Times shown in airport local time
Service date: · Scheduled arrival date; departure time unavailable (America/Los_Angeles)
Think UA5921 runs late today? Delayed is trading at 24¢ — pays out x4.23.
Will United Airlines UA 5921 from Ontario to San Francisco arrive on time, be delayed, or be cancelled on Sep 30?Flight details
Departure · UTC
- Scheduled
- Not available
- Estimated
- Not available
- Actual
- Not available
Arrival · UTC
- Scheduled
- Estimated
- Actual
- Not available
Market prices express trading expectations about a contract’s stated threshold. They do not confirm airline status. The linked market shows its terms and activity.
Also sold as AC4121, AC4285, CM2529
Recent arrivals
Dates below are arrival dates in the destination airport’s time zone. The detailed history uses service dates.
- 36 min early
Ontario → San Francisco
- 20 min early
Ontario → San Francisco
- 38 min early
Ontario → San Francisco
- 1 min early
Ontario → San Francisco
- On schedule (13 min behind)
Ontario → San Francisco
Is UA5921 usually late?
Observation window: Aug 31, 2026 – Sep 30, 2026
Percentages and delay figures appear once 10 arrivals are recorded.
On time means arriving no more than 15 minutes after the scheduled time; late means more than 15 minutes after. Cancelled and diverted flights are counted apart from arrivals. Results compare scheduled and actual arrival times. Cancelled or diverted flights are excluded. Some flights may be missing from the history.
At the airports today
San Francisco (SFO) departures
- Left more than 15 min late
- 111 of 306
- Cancelled today
- 2
Related flights
Flight history and details
| Service date | Departure | Arrival | Actual | Arrival delay (minutes) |
|---|---|---|---|---|
| Sep 28, 2026Arrived | Ontario | San Francisco | -36 | |
| Sep 27, 2026Arrived | Ontario | San Francisco | -20 | |
| Sep 26, 2026Arrived | Ontario | San Francisco | -38 | |
| Sep 25, 2026Arrived | Ontario | San Francisco | -1 | |
| Sep 24, 2026Arrived | Ontario | San Francisco | 13 |
Email me if UA5921 runs late
We email you if your next UA5921 flight in the coming day is more than 15 minutes late, cancelled or diverted. Alerts last 30 days. No account needed.