Flight profile · United Airlines
UA688
Washington (IAD) to Boston (BOS) · scheduled 5:10 PM – 6:56 PM
How UA688 performs
1,005 operations, 2023-07-01 to 2026-06-30.
UA688 arrived on time 61.5% of the time, against 77.6% for all IAD → BOS flights — this specific departure is 16.1 percentage points worse than the route as a whole. Against United Airlines’s own flights on this route it is 16.1 points worse.
Source: US DOT Bureau of Transportation Statistics · 1,005 operations between 2023-07-01 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| UA688 | 61.5% | 2.09% | 4 min | 18.2% | 1,005 |
| United Airlines on IAD → BOS | 77.6% | 1.48% | -5 min | 8.9% | 4,463 |
| All IAD → BOS flights | 77.6% | 1.47% | -5 min | 8.9% | 4,475 |
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30
By day of week
Does UA688 run worse on particular days?
Saturday is historically the most reliable day and Thursday the least, a gap of 20.6 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30 · Days with fewer than 120 operations are not scored.
Other routes UA688 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| MCI→IAD Kansas City to Washington | 2026-06-25 – 2026-06-30 | 6 | — |
| SEA→IAD Seattle to Washington | 2026-05-21 – 2026-06-24 | 34 | — |
| LAS→IAD Las Vegas to Washington | 2026-03-29 – 2026-05-20 | 53 | — |
| SLC→IAD Salt Lake City to Washington | 2025-10-26 – 2026-02-11 | 74 | — |
| LAX→IAD Los Angeles to Washington | 2025-06-26 – 2026-01-05 | 118 | 84.2% |
| SFO→LAX San Francisco to Los Angeles | 2025-12-18 – 2026-01-05 | 19 | — |
| BOS→EWR Boston to Newark | 2023-09-29 – 2025-09-30 | 42 | — |
| MCO→IAD Orlando to Washington | 2025-05-22 – 2025-06-25 | 35 | — |
| BOS→DEN Boston to Denver | 2024-05-23 – 2025-05-21 | 75 | — |
| PHX→IAD Phoenix to Washington | 2025-02-13 – 2025-03-05 | 21 | — |
| RSW→IAD Fort Myers to Washington | 2024-08-19 – 2025-02-12 | 141 | 83.2% |
| EWR→BOS Newark to Boston | 2024-06-02 – 2024-06-26 | 22 | — |
| AUS→IAD Austin to Washington | 2024-05-02 – 2024-05-22 | 21 | — |
| SRQ→IAD Sarasota/Bradenton to Washington | 2024-01-09 – 2024-03-06 | 58 | — |
| TPA→IAD Tampa to Washington | 2023-09-29 – 2023-09-30 | 2 | — |
| DEN→IAD Denver to Washington | 2023-08-01 – 2023-09-04 | 35 | — |
Because the same number has served different journeys, the statistics above describe only the route UA688 currently operates. Blending them would produce an average of two different flights.
Data and methodology
Calculated by FlyerIntel from 1,005 records of UA688 operating IAD → BOS, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.