Flight number record
UA 1451
United Airlines · Denver to Jacksonville
- Route
- DEN → JAX
- Departs
- 10:05
- Flights
- 292
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1451, check with United Airlines.
UA 1451 lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 292 flights, with a median arrival 7 minutes early.
Set against the rest of the country, UA 1451's record is 6 points better than the US average of 77.3%. That gap is worth roughly 55 fewer late arrivals for every thousand flights.
Key figures
On time
82.8%
Arrivals under 15 minutes late, of 291 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
4.1%
National rate is 8.3%
These figures cover 292 flights between September 2025 and August 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When UA 1451 flies
UA 1451 flies DEN to JAX without a single fixed slot. Its most common scheduled departure was 10:05, used on 88 of 292 flights, with 09:55 (43 flights) and 10:00 (40 flights) next.
- Departs 10:0588 flights30.1%
- Departs 09:5543 flights14.7%
- Departs 10:0040 flights13.7%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 10:05 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1451 runs level with that at 82.8%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
UA 1451 next to DEN to JAX
Every carrier on DEN to JAX combined arrived on time 76.5% of the time across 1,044 flights, so UA 1451 is 6 points ahead of it. United flew 661 flights on the same city pair under all its flight numbers, including this one, and those ran 82.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1451thin sample | 292 | 82.8% | 61 min | 0.00% | B+ |
| All United Airlines on DEN–JAX | 661 | 82.3% | 58 min | 0.00% | B+ |
| All carriers on DEN–JAX | 1,044 | 76.5% | 55 min | 0.00% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1451 quarter by quarter
UA 1451 did not run the same all year. Its best quarter was Jan–Mar 2026 at 88.8% on time and its weakest Jul–Sep 2026 at 64.4%, a swing of 24 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 20256 flights—
- Oct–Dec 202592 flights83.7%
- Jan–Mar 202690 flights88.8%
- Apr–Jun 202659 flights88.1%
- Jul–Sep 202645 flights64.4%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1451 did best on Tuesday at 100.0% on time and worst on Saturday at 76.1%. Each day rests on about 42 flights, so a gap of 24 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1451 runs when it is late
UA 1451 often beats the schedule: 74 of 291 completed flights, 25%, arrived 15 minutes or more early. The 50 late arrivals split 17 under half an hour, 21 between 30 and 60 minutes, and 12 an hour or more.
- 15+ min early74 flights25.4%
- Within 15 min167 flights57.4%
- 15–29 min late17 flights5.8%
- 30–59 min late21 flights7.2%
- 1–2 hours late9 flights3.1%
- 2+ hours late3 flights1.0%
Scale runs 0% to 100%.
Share of 291 completed flights by arrival against schedule.
14 of 47 late departures made up the time and arrived on time, 30% of them. In the other direction, 17 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at JAX.
The worst days
Worst days for UA 1451
The latest arrival of the period was on 19 December 2025, 5 hours 30 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 December 2025 | 5 hours 30 minutes | Carrier |
| 7 June 2026 | 5 hours 27 minutes | Late-arriving aircraft |
| 15 August 2026 | 4 hours 3 minutes | Carrier |
| 9 August 2026 | 1 hour 46 minutes | National Airspace System |
| 2 January 2026 | 1 hour 34 minutes | Carrier |
Delay causes
Why UA 1451 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 3,025 reported delay minutes.
- 36%Carrier
- 34%National Airspace System
- 28%Late-arriving aircraft
- 1%Extreme weather
34% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,037 minutes out of 3,025, against a national NAS share of 21%. The split is drawn from 3,025 delay minutes reported on UA 1451.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 4.1% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,446 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The same number turns up on seven other city pairs in the data, including PSC to DEN (32), JAX to ORD (25) and MTJ to DEN (24), but none flew often enough under UA 1451 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to JAX only.
One caution: this is a thin sample. 292 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking UA 1451
For a booking, read UA 1451 as 82.8% on time with 0.00% cancelled over 292 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to JAX, every carrier and departure
- JAX to DEN, the return direction
- Denver International (DEN) delay statistics
- Jacksonville International (JAX) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.