Flight profile · United Airlines
UA1281
Denver (DEN) to San Diego (SAN) · scheduled 3:55 PM – 5:37 PM
How UA1281 performs
1,061 operations, July 2023 – July 2026.
UA1281 arrived on time 82.2% of the time, against 75.5% for all DEN → SAN flights, so this departure is 6.7 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 2.1 points better.
Source: US DOT Bureau of Transportation Statistics · 1,061 operations, July 2023 – July 2026 · If UA1281 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1281 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| UA1281 | 82.2% | 1.51% | -6 min | 6.5% | 1,061 |
| United Airlines on DEN → SAN | 80.1% | 0.85% | -7 min | 6.9% | 6,597 |
| All DEN → SAN flights | 75.5% | 0.98% | -4 min | 7.4% | 17,468 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why UA1281 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1281 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
Does a late aircraft delay this flight?
How often the plane that flies UA1281 comes in late, and what that does to the departure.
The aircraft flying UA1281 came in 15 or more minutes late on 11% 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, 946 of 1,045 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.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late |
|---|---|
| UA1281 | 11% |
| Network, same turn | 17% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often UA1281’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
From pushback to gate
When it leaves DEN late, does that still matter by the time it reaches SAN?
UA1281 pushes back an average of 10.6 minutes late and reaches the gate at SAN an average of 3.4 minutes late. The 7.2 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 18.5 minutes on the taxiways at DEN is about what any departure from the airport in that hour spends.
On arrival at SAN, UA1281 spends 3.4 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 2.6 minutes shorter than a typical SAN arrival (6.0 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 SAN. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 52,619 departures from DEN scheduled in the clock hour UA1281 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 UA1281’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves DEN
Part of any flight’s record belongs to the clock rather than to the flight. UA1281 has one departure time, so this is what that time is worth.
On-time arrival rate. 52,619 departures from DEN are scheduled in the 3 PM–4 PM hour over the period, against 963,099 across the whole day.
UA1281 is scheduled out of DEN at 3:55 PM, in the 3 PM–4 PM bank. Departures from DEN in that hour arrive on time 72.9% of the time against 76.0% across the airport’s whole day — the slot alone is worth 3.1 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.
By day of week
Does UA1281 run worse on particular days?
Saturday is historically the most reliable day and Thursday the least, a gap of 5.7 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.
Other routes UA1281 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 |
|---|---|---|---|
| MSP→DEN Minneapolis to Denver | February 12, 2026 – March 4, 2026 | 21 | — |
| ORD→MSP Chicago to Minneapolis | February 12, 2026 – March 4, 2026 | 21 | — |
| CLE→DEN Cleveland to Denver | December 18, 2025 – January 5, 2026 | 19 | — |
| EWR→CLE Newark to Cleveland | October 26, 2025 – December 1, 2025 | 37 | — |
| RAP→DEN Rapid City to Denver | May 1, 2025 – August 18, 2025 | 110 | 76.9% |
| ORD→RAP Chicago to Rapid City | May 22, 2025 – June 25, 2025 | 35 | — |
| SEA→DEN Seattle to Denver | September 29, 2023 – September 25, 2024 | 68 | — |
| SAN→SFO San Diego to San Francisco | January 9, 2024 – March 6, 2024 | 58 | — |
Because the same number has served different journeys, the statistics above describe only the route UA1281 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
41 min late
against a median of 6 min early
Percentiles over 1,061 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA2309 | United Airlines | 87.6% | 12 min early | 1,049 |
| UA1302 | United Airlines | 87.1% | 9 min early | 689 |
| F92817 | Frontier Airlines | 82.5% | 10 min early | 653 |
| UA1281 this flight | United Airlines | 82.2% | 6 min early | 1,061 |
| F94989 | Frontier Airlines | 70.1% | 3 min early | 623 |
| UA540 | United Airlines | 68.9% | 0 min early | 1,039 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1281 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.
Data and methodology
Calculated by FlyerIntel from 1,061 records of UA1281 operating DEN → SAN, 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.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed