About 1 in 4 UA 4304 flights from Washington arrived 15+ minutes late, diverted or cancelled over the past year (28%); 0.6% were cancelled. The typical flight landed 2 minutes early.
UA 4304: IAD → TYS
Scheduled to leave Washington at 10:10 p.m. local time, operated by CommutAir as C5 4304. Over the past year it arrived on time 72% of the time (180 flights), in line with other UA flights on the route at that hour (72%). Last seen in the data Aug 31, 2026.
Usually United Airlines's last flight of the day from Washington to Knoxville (100% of days). United Airlines's last IAD–TYS flight was cancelled 1.6% of the time, against 1.1% for its earlier ones. If it's cancelled, the next United Airlines flight is usually around 9:00 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 28 | 82% |
| Tuesday | 25 | 80% |
| Wednesday | 23 | 74% |
| Thursday | 25 | 76% |
| Friday | 26 | 58% |
| Saturday | 26 | 65% |
| Sunday | 27 | 67% |
Why it was late
All flights IAD → TYS · Connecting off UA 4304? Check the risk
Questions
How often is UA 4304 from IAD to TYS late?
United Airlines 4304 from Washington, DC to Knoxville, TN arrived 15 or more minutes late, was diverted or was cancelled on 28% of 180 scheduled flights between September 2025 and August 2026. 0.6% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check United Airlines for today's flight. Method.