UA2400

UA2400 arrived on time 62.0% of the time, against 74.6% for all BOS → SFO flights, so this departure is 12.6 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 16.7 points worse.

Source: US DOT Bureau of Transportation Statistics · 1,033 operations, July 2023 – July 2026 · If UA2400 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.

This flight runs unusually far behind the carrier's own average on this route, worse than 96% of 11,589 comparable flight numbers.

62.0% on time for this specific departure, against 78.7% for the same carrier's other flights on this route.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · The one thing about this specific departure that ranks most extreme against every other published flight number, out of everything FlyerIntel checks — shown only when something clears a real statistical bar, not for every flight.

UA2400 has cancelled 2.03% of its scheduled departures (21 of 1,033), against 1.03% for all BOS → SFO flights — this specific departure cancels 1.0 percentage points more often than the route as a whole. Different flight numbers on the same route can carry different aircraft, crews and schedules, so this is a fact about UA2400 specifically, not about the route it flies.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026

Share of the delay minutes US DOT attributed to each cause for UA2400 on BOS → SFO. Only delays of 15 minutes or more are attributed.

Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026

When the aircraft came in 15 or more minutes late, UA2400 pushed back an average of 77 minutes late; when it came in on time or early, an average of 16 minutes late.

Each departure is matched to the flight the same aircraft flew into BOS just before it, using the tail number in the DOT file, 991 of 1,012 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.

Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026

UA2400 pushes back an average of 29.0 minutes late and reaches the gate at SFO an average of 21.0 minutes late. The 8.0 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. Its 23.9 minutes on the taxiways at BOS is about what any departure from the airport in that hour spends.

On arrival at SFO, UA2400 spends 8.9 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 1.0 minutes longer than a typical SFO arrival (7.9 min).

Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached SFO. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 27,363 departures from BOS scheduled in the clock hour UA2400 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at SFO (436,060 flights), not just UA2400’s own. More on taxi time.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026

UA2400 is scheduled out of BOS at 6:18 PM, in the 6 PM–7 PM bank. Departures from BOS in that hour arrive on time 66.3% of the time against 77.2% across the airport’s whole day — the slot alone is worth 10.9 points worse before anything about this particular flight is considered.

The two airport figures cover every departure from BOS to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Hours below 120 departures are not scored.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.

Because the same number has served different journeys, the statistics above describe only the route UA2400 currently operates. Blending them would produce an average of two different flights.

Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026

Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA2400 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.

• B6733 BOS→SFO JetBlue on the same route, departs 6:30 PM, on time 68.2%
• B6333 BOS→SFO JetBlue on the same route, departs 8:59 PM, on time 60.5%
• B61833 BOS→SFO JetBlue on the same route, departs 9:50 AM, on time 79.3%