Flight number record
UA 2666
United Airlines · Denver to Santa Ana
- Route
- DEN → SNA
- Departs
- 07:40
- Flights
- 340
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2666, check with United Airlines.
UA 2666 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 17 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 340 flights, with a median arrival 14 minutes early.
Set against the rest of the country, UA 2666's record is 17 points better than the US average of 77.3%. That gap is worth roughly 174 fewer late arrivals for every thousand flights.
Key figures
On time
94.7%
Arrivals under 15 minutes late, of 338 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
1.8%
National rate is 8.3%
These figures cover 340 flights between September 2025 and August 2026. The median arrival is 14 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.
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Schedule
When UA 2666 flies
UA 2666 flies DEN to SNA without a single fixed slot. Its most common scheduled departure was 07:40, used on 103 of 340 flights, with 07:50 (65 flights) and 08:10 (53 flights) next.
- Departs 07:40103 flights30.3%
- Departs 07:5065 flights19.1%
- Departs 08:1053 flights15.6%
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 07:40 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 2666 runs 5 points better at 94.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 2666 next to DEN to SNA
Every carrier on DEN to SNA combined arrived on time 80.6% of the time across 3,710 flights, so UA 2666 is 14 points ahead of it. United flew 1,901 flights on the same city pair under all its flight numbers, including this one, and those ran 85.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 16 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2666thin sample | 340 | 94.7% | 47 min | 0.00% | A+ |
| All United Airlines on DEN–SNA | 1,901 | 85.3% | 48 min | 0.16% | A+ |
| All carriers on DEN–SNA | 3,710 | 80.6% | 45 min | 0.16% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2666 quarter by quarter
Quarter by quarter UA 2666 held fairly steady: 92.1% in Oct–Dec 2025, 93.3% in Jan–Mar 2026, 95.6% in Apr–Jun 2026 and 98.4% in Jul–Sep 2026. A spread of 6 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 20256 flights—
- Oct–Dec 202591 flights92.1%
- Jan–Mar 202690 flights93.3%
- Apr–Jun 202691 flights95.6%
- Jul–Sep 202662 flights98.4%
Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2666 ranged from 89.6% on Wednesday to 98.0% on Sunday. With about 49 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 2666 runs when it is late
UA 2666 often beats the schedule: 161 of 338 completed flights, 48%, arrived 15 minutes or more early. Most of the lateness is short. 11 of the 18 late arrivals were under half an hour behind, and 6 reached an hour or more.
- 15+ min early161 flights47.6%
- Within 15 min159 flights47.0%
- 15–29 min late11 flights3.3%
- 30–59 min late1 flights0.3%
- 1–2 hours late4 flights1.2%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 338 completed flights by arrival against schedule.
Only 9 of 338 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for UA 2666
The latest arrival of the period was on 13 May 2026, 2 hours 31 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 May 2026 | 2 hours 31 minutes | Late-arriving aircraft |
| 26 January 2026 | 2 hours 26 minutes | Late-arriving aircraft |
| 10 November 2025 | 1 hour 40 minutes | Late-arriving aircraft |
| 17 March 2026 | 1 hour 20 minutes | Carrier |
| 6 March 2026 | 1 hour 5 minutes | National Airspace System |
Delay causes
Why UA 2666 runs late
Late-arriving aircraft accounts for 53% of the 847 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Late-arriving aircraft
- 29%National Airspace System
- 18%Carrier
53% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 847 reported delay minutes here, that single category outweighs weather by 53 to one. The split is drawn from 847 delay minutes reported on UA 2666.
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 1.8% 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 846 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 one other city pair in the data, including ORD to DEN (158), but none flew often enough under UA 2666 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to SNA only.
One caution: this is a thin sample. 340 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 2666
For a booking, UA 2666 has one of the better records a US domestic flight can show: 94.7% on time and 0.00% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- DEN to SNA, every carrier and departure
- SNA to DEN, the return direction
- United Airlines 1320 on the same route86.0%
- Denver International (DEN) delay statistics
- John Wayne Airport (SNA) 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
- Why the first flight of the morning is statistically safest
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.