UA1638

UA1638 arrived on time 89.8% of the time, against 78.9% for all DEN → LAX flights, so this departure is 10.9 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 7.9 points better.

Source: US DOT Bureau of Transportation Statistics · 674 operations, September 2024 – July 2026 · If UA1638 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 ahead of the DEN → LAX route as a whole, better than 92% of 11,788 comparable flight numbers.

89.8% on time for this specific departure, against 78.9% for every DEN → LAX flight.

Source: FlyerIntel analysis of US DOT BTS data · September 2024 – 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.

Source: FlyerIntel analysis of US DOT BTS data · September 2024 – July 2026

Share of the delay minutes US DOT attributed to each cause for UA1638 on DEN → LAX. Only delays of 15 minutes or more are attributed.

Source: US DOT Bureau of Transportation Statistics · Data covering September 2024 – July 2026

UA1638 is usually the aircraft’s first flight of the day: the schedule gives it a median of 8.8 hours on the ground at DEN, so its “inbound” is mostly the aircraft’s arrival the evening before.

The aircraft flying UA1638 came in 15 or more minutes late on 17% 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 DEN just before it, using the tail number in the DOT file, 495 of 674 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 September 2024 – July 2026

UA1638 pushes back an average of 1.8 minutes early and reaches the gate at LAX an average of 4.4 minutes early. The 2.6 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 20.2 minutes on the taxiways at DEN, 1.0 minutes longer than a typical DEN departure in the same hour.

On arrival at LAX, UA1638 spends 14.8 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 4.1 minutes longer than a typical LAX arrival (10.7 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 LAX. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 53,796 departures from DEN scheduled in the clock hour UA1638 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at LAX (595,170 flights), not just UA1638’s own. More on taxi time.

Source: FlyerIntel analysis of US DOT BTS data · September 2024 – July 2026

UA1638 is scheduled out of DEN at 8:00 AM, in the 8 AM–9 AM bank. Departures from DEN in that hour arrive on time 86.8% of the time against 76.0% across the airport’s whole day — the slot alone is worth 10.8 points better before anything about this particular flight is considered.

The two airport figures cover every departure from DEN 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 · September 2024 – July 2026 · Hours below 120 departures are not scored.

Because the same number has served different journeys, the statistics above describe only the route UA1638 currently operates. Blending them would produce an average of two different flights.

Source: US DOT Bureau of Transportation Statistics · Data covering September 2024 – July 2026

Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1638 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.

• DL2002 DEN→LAX Delta Air Lines on the same route, departs 6:15 AM, on time 88.2%
• UA405 DEN→LAX United Airlines on the same route, departs 9:45 AM, on time 87.9%
• UA1093 DEN→LAX United Airlines on the same route, departs 6:00 AM, on time 91.2%
• UA1442 DEN→LGA United Airlines flight out of DEN, DEN to LGA, departs 7:45 AM, on time 89.0%