Flight Reliability
UA 4866 · United Airlines
ROA → Washington (ROA–IAD)100% of its flights flew this route. The rest (TUL–IAH) are included in these numbers.
84
Pretty Reliable
WanderNerd Reliability Score
- 86%
- Arrive within 15 minutes
- 10 min
- Average arrival delay
- 2.6%
- Cancelled
- 15 min early
- Median arrival delay
Based on 234 historical flights. Data through May 2026.
What the data says
Sunday scaries are real for this one.
UA 4866 arrived on time 100% of the time on Tuesdays and just 79% on Sundays. That gap is worth planning around.
Better than the United Airlines network average.
UA 4866 arrived on time 86% of the time, versus 79% across the United Airlines network.
The breakdown
- Mon82%(28 flights)
- Tue100%(28 flights)
- Wed86%(29 flights)
- Thu86%(35 flights)
- Fri85%(33 flights)
- Sat87%(37 flights)
- Sun79%(38 flights)
100%
Apr
Jun 74% → Apr 100% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 74% | 27 |
| July 2025 | 67% | 15 |
| August 2025 | 79% | 24 |
| September 2025 | 87% | 30 |
| October 2025 | 94% | 31 |
| November 2025 | 93% | 27 |
| December 2025 | 93% | 15 |
| March 2026 | 75% | 24 |
| April 2026 | 100% | 29 |
- Departures on time
- 87%
- Diverted
- 0%
- Flights flown
- 228
- Months covered
- 11
Same route, other flights
Keep nerding
Based on 234 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.