Flight number record
OO 4001
SkyWest Airlines · Los Angeles to San Diego
- Route
- LAX → SAN
- Departs
- 14:11
- Flights
- 289
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4001, check with SkyWest Airlines. SkyWest Airlines flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
OO 4001 lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That rests on 289 flights, with a median arrival 2 minutes early.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 288 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.35%
National rate is 1.89%
1 hour+ late
4.5%
National rate is 8.3%
These figures cover 289 flights between September 2025 and August 2026. The median arrival is 2 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 OO 4001 flies
OO 4001 flies LAX to SAN without a single fixed slot. Its most common scheduled departure was 14:11, used on 86 of 289 flights, with 14:30 (56 flights) and 14:02 (36 flights) next.
- Departs 14:1186 flights29.8%
- Departs 14:3056 flights19.4%
- Departs 14:0236 flights12.5%
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 14:11 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and OO 4001 runs 7 points better at 79.2%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
OO 4001 next to LAX to SAN
Every carrier on LAX to SAN combined arrived on time 83.2% of the time across 2,452 flights, so OO 4001 is 4 points behind it. SkyWest flew 2,162 flights on the same city pair under all its flight numbers, including this one, and those ran 83.9% on time. Across its whole network SkyWest Airlines managed 78.7%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4001thin sample | 289 | 79.2% | 49 min | 0.35% | B+ |
| All SkyWest Airlines on LAX–SAN | 2,162 | 83.9% | 62 min | 1.06% | B |
| All carriers on LAX–SAN | 2,452 | 83.2% | 60 min | 0.94% | B+ |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4001 quarter by quarter
OO 4001 did not run the same all year. Its best quarter was Apr–Jun 2026 at 91.7% on time and its weakest Jul–Sep 2026 at 61.3%, a swing of 30 points on roughly 72 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 202517 flights—
- Oct–Dec 202567 flights78.8%
- Jan–Mar 202683 flights83.1%
- Apr–Jun 202660 flights91.7%
- Jul–Sep 202662 flights61.3%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, OO 4001 did best on Tuesday at 95.5% on time and worst on Monday at 66.7%. Each day rests on about 41 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 4001 runs when it is late
The 60 late arrivals split 20 under half an hour, 27 between 30 and 60 minutes, and 13 an hour or more.
- 15+ min early23 flights8.0%
- Within 15 min205 flights71.2%
- 15–29 min late20 flights6.9%
- 30–59 min late27 flights9.4%
- 1–2 hours late8 flights2.8%
- 2+ hours late5 flights1.7%
Scale runs 0% to 100%.
Share of 288 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 44 departures that left 15 minutes late or more, only 2 made it up before arrival. In the other direction, 18 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 SAN.
The worst days
Worst days for OO 4001
The latest arrival of the period was on 5 January 2026, 2 hours 52 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 5 January 2026 | 2 hours 52 minutes | Carrier |
| 27 October 2025 | 2 hours 43 minutes | Carrier |
| 19 December 2025 | 2 hours 17 minutes | Carrier |
| 16 February 2026 | 2 hours 9 minutes | National Airspace System |
| 4 May 2026 | 2 hours 5 minutes | Carrier |
Delay causes
Why OO 4001 runs late
Carrier accounts for 62% of the 2,919 delay minutes carriers reported here, and the remaining four split what is left.
- 62%Carrier
- 33%National Airspace System
- 5%Extreme weather
The largest share of delay minutes, 62%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,814 of the 2,919 delay minutes reported here. The split is drawn from 2,919 delay minutes reported on OO 4001.
Cancellations are rare at 0.35%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is 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 4.5% 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 same number turns up on three other city pairs in the data, including SAN to LAX (95), PDX to SEA (16) and SEA to PDX (16), but none flew often enough under OO 4001 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAX to SAN only.
One caution: this is a thin sample. 289 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 OO 4001
For a booking, read OO 4001 as 79.2% on time with 0.35% cancelled over 289 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- LAX to SAN, every carrier and departure
- SAN to LAX, the return direction
- SkyWest Airlines 3746 on the same route86.6%
- SkyWest Airlines 4643 on the same route87.5%
- SkyWest Airlines 4087 on the same route79.5%
- SkyWest Airlines 5415 on the same route85.3%
- Los Angeles International (LAX) delay statistics
- San Diego International (SAN) delay statistics
- SkyWest Airlines on-time record
- Every SkyWest 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 SkyWest 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.