UA638

UA638 arrived on time 89.4% of the time, against 80.0% for all SFO → HNL flights, so this departure is 9.4 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 6.7 points better.

Source: US DOT Bureau of Transportation Statistics · 708 operations, October 2023 – July 2026 · If UA638 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.

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

Share of the delay minutes US DOT attributed to each cause for UA638 on SFO → HNL. Only delays of 15 minutes or more are attributed.

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

The aircraft flying UA638 came in 15 or more minutes late on 18% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.

Each departure is matched to the flight the same aircraft flew into SFO just before it, using the tail number in the DOT file, 509 of 708 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 October 2023 – July 2026

UA638 pushes back an average of 8.9 minutes late and reaches the gate at HNL an average of 6.5 minutes early. The 15.4 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. It spends 23.0 minutes on the taxiways at SFO, 3.0 minutes longer than a typical SFO departure in the same hour.

On arrival at HNL, UA638 spends 7.0 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 1.3 minutes shorter than a typical HNL arrival (8.3 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 HNL. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 17,402 departures from SFO scheduled in the clock hour UA638 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at HNL (186,355 flights), not just UA638’s own. More on taxi time.

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

UA638 is scheduled out of SFO at 7:10 PM, in the 7 PM–8 PM bank. Departures from SFO in that hour arrive on time 75.9% of the time against 78.7% across the airport’s whole day, so the hour UA638 leaves in is an ordinary one for SFO and explains nothing about its record either way.

The two airport figures cover every departure from SFO 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 · October 2023 – July 2026 · Hours below 120 departures are not scored.

Because the same number has served different journeys, the statistics above describe only the route UA638 currently operates. Blending them would produce an average of two different flights.

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

Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA638 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.

• UA1509 SFO→HNL United Airlines on the same route, departs 4:55 PM, on time 80.8%
• UA300 SFO→HNL United Airlines on the same route, departs 1:40 PM, on time 81.4%
• UA2380 SFO→HNL United Airlines on the same route, departs 11:10 AM, on time 75.9%