Flight Reliability
UA 4986 · United Airlines
Washington → MDT (IAD–MDT)
89
Pretty Reliable
WanderNerd Reliability Score
- 85%
- Arrive within 15 minutes
- 9 min
- Average arrival delay
- 1.1%
- Cancelled
- 9 min early
- Median arrival delay
Based on 276 historical flights. Data through May 2026.
What the data says
Sunday scaries are real for this one.
UA 4986 arrived on time 90% of the time on Fridays. On Sundays: 81%.
A bit ahead of the IAD–MDT route.
UA 4986 arrived on time 85% of the time, versus 81% across the IAD–MDT route.
A bit ahead of the United Airlines network.
UA 4986 arrived on time 85% of the time, versus 79% across the United Airlines network.
Trending in the right direction.
UA 4986 arrived on time 92% of the time over the last three months in the data, compared with 72% in the three months before that.
The breakdown
- Mon82%(39 flights)
- Tue83%(41 flights)
- Wed85%(41 flights)
- Thu87%(45 flights)
- Fri90%(48 flights)
- Sat87%(23 flights)
- Sun81%(36 flights)
96%
May
Jun 79% → May 96% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 79% | 24 |
| July 2025 | 84% | 19 |
| August 2025 | 83% | 12 |
| September 2025 | 94% | 18 |
| October 2025 | 96% | 27 |
| December 2025 | 63% | 27 |
| January 2026 | 75% | 28 |
| February 2026 | 79% | 24 |
| March 2026 | 87% | 31 |
| April 2026 | 93% | 30 |
| May 2026 | 96% | 24 |
- Departures on time
- 86%
- Diverted
- 0%
- Flights flown
- 273
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 276 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.