Flight number record
UA 2666
United Airlines · Denver to Santa Ana
- Route
- DEN → SNA
- Departs
- 07:50
- Flights
- 327
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 2666, check with United Airlines.
UA 2666 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 15 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 45 minutes. That rests on 327 flights, with a median arrival 12 minutes early.
Set against the rest of the country, UA 2666's record is 15 points better than the US average of 77.6%. That gap is worth roughly 153 fewer late arrivals for every thousand flights.
Key figures
On time
92.9%
Arrivals under 15 minutes late, of 325 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
1 hour+ late
2.2%
National rate is 8.1%
These figures cover 327 flights between July 2025 and June 2026. The median arrival is 12 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.
Schedule
When UA 2666 flies
UA 2666 flies DEN to SNA without a single fixed slot. Its most common scheduled departure was 07:50, used on 114 of 327 flights, with 08:10 (53 flights) and 07:40 (41 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 07:50114 flights34.9%
- Departs 08:1053 flights16.2%
- Departs 07:4041 flights12.5%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:50 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 4 points better at 92.9%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
UA 2666 next to DEN to SNA
Every carrier on DEN to SNA combined arrived on time 80.1% of the time across 3,696 flights, so UA 2666 is 13 points ahead of it. United flew 1,870 flights on the same city pair under all its flight numbers, including this one, and those ran 84.8% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2666thin sample | 327 | 92.9% | 46 min | 0.00% | A+ |
| All United Airlines on DEN–SNA | 1,870 | 84.8% | 49 min | 0.32% | B+ |
| All carriers on DEN–SNA | 3,696 | 80.1% | 47 min | 0.35% | B+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 2666 quarter by quarter
Quarter by quarter UA 2666 held fairly steady: 89.1% in Jul–Sep 2025, 92.1% in Oct–Dec 2025, 93.3% in Jan–Mar 2026 and 95.6% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202555 flights89.1%
- Oct–Dec 202591 flights92.1%
- Jan–Mar 202690 flights93.3%
- Apr–Jun 202691 flights95.6%
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2666 ranged from 89.1% on Wednesday to 95.7% on Tuesday. With about 47 flights behind each day, a spread of 7 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why UA 2666 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 51% of the 1,056 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 51%Late-arriving aircraft
- 29%National Airspace System
- 20%Carrier
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 1,056 reported delay minutes here, that single category outweighs weather by 51 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 1,056 delay minutes reported on UA 2666.
Cancellations are rare at 0.00%, below the national 1.81% 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 2.2% land an hour or more behind schedule, against 8.1% 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
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. 327 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: 92.9% 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 route85.4%
- Frontier Airlines 4371 on the same route86.9%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.