Flight profile · United Airlines
UA1561
Denver (DEN) to San Francisco (SFO) · scheduled 11:35 AM – 1:23 PM
How UA1561 performs
969 operations, September 2023 – July 2026.
UA1561 arrived on time 73.6% of the time, against 67.8% for all DEN → SFO flights, so this departure is 5.8 percentage points better than the route as a whole.
Source: US DOT Bureau of Transportation Statistics · 969 operations, September 2023 – July 2026 · If UA1561 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1561 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 |
|---|---|---|---|---|---|
| UA1561 | 73.6% | 0.10% | -4 min | 8.4% | 969 |
| United Airlines on DEN → SFO | 73.3% | 0.70% | -4 min | 9.6% | 10,399 |
| All DEN → SFO flights | 67.8% | 0.69% | 0 min | 11.4% | 17,109 |
Source: FlyerIntel analysis of US DOT BTS data · September 2023 – July 2026
Why UA1561 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1561 on DEN → SFO. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering September 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA1561 comes in late, and what that does to the departure.
The aircraft flying UA1561 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, 896 of 968 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 |
|---|---|
| UA1561 | 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 UA1561’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 September 2023 – July 2026
From pushback to gate
When it leaves DEN late, does that still matter by the time it reaches SFO?
UA1561 pushes back an average of 15.4 minutes late and reaches the gate at SFO an average of 9.7 minutes late. The 5.8 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 22.5 minutes on the taxiways at DEN, 2.6 minutes longer than a typical DEN departure in the same hour.
On arrival at SFO, UA1561 spends 7.3 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 SFO 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 SFO. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 94,079 departures from DEN scheduled in the clock hour UA1561 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 UA1561’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · September 2023 – July 2026
The hour it leaves DEN
Part of any flight’s record belongs to the clock rather than to the flight. UA1561 has one departure time, so this is what that time is worth.
On-time arrival rate. 94,079 departures from DEN are scheduled in the 11 AM–12 PM hour over the period, against 963,099 across the whole day.
UA1561 is scheduled out of DEN at 11:35 AM, in the 11 AM–12 PM bank. Departures from DEN in that hour arrive on time 80.0% of the time against 76.0% across the airport’s whole day — the slot alone is worth 4.0 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 2023 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does UA1561 run worse on particular days?
Tuesday is historically the most reliable day and Monday the least, a gap of 9.3 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · September 2023 – July 2026 · Days with fewer than 120 operations are not scored.
Other routes UA1561 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 |
|---|---|---|---|
| SFO→SAN San Francisco to San Diego | May 21, 2026 – July 31, 2026 | 71 | — |
| FCA→DEN Kalispell to Denver | June 25, 2026 – July 27, 2026 | 21 | — |
| SFO→ONT San Francisco to Ontario | March 5, 2026 – May 20, 2026 | 76 | — |
| GTF→DEN Great Falls to Denver | March 6–28, 2026 | 23 | — |
| SFO→PHX San Francisco to Phoenix | June 27, 2024 – February 11, 2026 | 591 | 84.0% |
| MCO→DEN Orlando to Denver | December 18, 2025 – January 5, 2026 | 15 | — |
| SDF→DEN Louisville to Denver | October 26, 2025 – December 1, 2025 | 37 | — |
| MSP→DEN Minneapolis to Denver | May 1–21, 2025 | 21 | — |
| ORF→DEN Norfolk to Denver | February 13, 2025 – March 5, 2025 | 21 | — |
| MIA→DEN Miami to Denver | December 19, 2024 – January 6, 2025 | 19 | — |
| SYR→DEN Syracuse to Denver | October 27, 2024 – December 2, 2024 | 37 | — |
| TPA→DEN Tampa to Denver | December 21, 2023 – October 26, 2024 | 50 | — |
| STL→DEN St. Louis to Denver | August 19, 2024 – September 25, 2024 | 38 | — |
| MEM→DEN Memphis to Denver | May 23, 2024 – June 30, 2024 | 39 | — |
| SFO→PDX San Francisco to Portland | July 1, 2023 – March 6, 2024 | 211 | 82.3% |
| MTJ→DEN Montrose to Denver | February 15–25, 2024 | 4 | — |
| TUL→DEN Tulsa to Denver | January 11, 2024 – February 14, 2024 | 29 | — |
| ORD→SFO Chicago to San Francisco | August 18, 2023 | 1 | — |
Because the same number has served different journeys, the statistics above describe only the route UA1561 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.
52 min late
against a median of 4 min early
Percentiles over 969 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering September 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 |
|---|---|---|---|---|
| UA1812 | United Airlines | 78.6% | 7 min early | 655 |
| UA1561 this flight | United Airlines | 73.6% | 4 min early | 969 |
| UA1007 | United Airlines | 66.9% | 0 min early | 786 |
| F93439 | Frontier Airlines | 65.3% | 2 min late | 676 |
| UA2681 | United Airlines | 60.3% | 4 min late | 837 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1561 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 969 records of UA1561 operating DEN → SFO, 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
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