UA540

UA540 arrived on time 68.9% of the time, against 75.5% for all DEN → SAN flights, so this departure is 6.6 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 11.2 points worse.

Source: US DOT Bureau of Transportation Statistics · 1,039 operations, July 2023 – July 2026 · If UA540 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 91% of 11,589 comparable flight numbers.

68.9% on time for this specific departure, against 80.1% 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.

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

Share of the delay minutes US DOT attributed to each cause for UA540 on DEN → SAN. 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, UA540 pushed back an average of 38 minutes late; when it came in on time or early, an average of 8 minutes late.

Each departure is matched to the flight the same aircraft flew into DEN just before it, using the tail number in the DOT file, 895 of 1,029 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

UA540 pushes back an average of 17.0 minutes late and reaches the gate at SAN an average of 13.0 minutes late. The 4.0 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. It spends 21.4 minutes on the taxiways at DEN, 1.5 minutes longer than a typical DEN departure in the same hour.

On arrival at SAN, UA540 spends 5.3 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 about what any arrival at SAN spends on the ground before reaching the gate.

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 SAN. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 81,727 departures from DEN scheduled in the clock hour UA540 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at SAN (297,664 flights), not just UA540’s own. More on taxi time.

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

UA540 is scheduled out of DEN at 7:40 PM, in the 7 PM–8 PM bank. Departures from DEN in that hour arrive on time 66.9% of the time against 76.0% across the airport’s whole day — the slot alone is worth 9.2 points worse 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 · 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 UA540 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. UA540 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.

• F94989 DEN→SAN Frontier Airlines on the same route, departs 10:29 PM, on time 70.1%
• UA1281 DEN→SAN United Airlines on the same route, departs 3:55 PM, on time 82.2%
• UA2309 DEN→SAN United Airlines on the same route, departs 7:45 AM, on time 87.6%