Flight number record
OO 4099
SkyWest Airlines · Los Angeles to Reno
- Route
- LAX → RNO
- Departs
- 08:20
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4099, 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 4099 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 18 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 365 flights, with a median arrival 16 minutes early.
Set against the rest of the country, OO 4099's record is 18 points better than the US average of 77.3%. That gap is worth roughly 180 fewer late arrivals for every thousand flights.
Key figures
On time
95.3%
Arrivals under 15 minutes late, of 363 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
2.2%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 16 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 4099 flies
OO 4099 flies LAX to RNO without a single fixed slot. Its most common scheduled departure was 08:20, used on 172 of 365 flights, with 09:40 (38 flights) next.
- Departs 08:20172 flights47.1%
- Departs 09:4038 flights10.4%
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 08:20 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and OO 4099 runs 11 points better at 95.3%. 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
OO 4099 next to LAX to RNO
Every carrier on LAX to RNO combined arrived on time 89.1% of the time across 2,470 flights, so OO 4099 is 6 points ahead of it. SkyWest flew 1,973 flights on the same city pair under all its flight numbers, including this one, and those ran 91.7% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 17 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4099 | 365 | 95.3% | 64 min | 0.55% | A+ |
| All SkyWest Airlines on LAX–RNO | 1,973 | 91.7% | 63 min | 0.30% | A+ |
| All carriers on LAX–RNO | 2,470 | 89.1% | 56 min | 0.40% | A+ |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4099 quarter by quarter
Quarter by quarter OO 4099 held fairly steady: 100.0% in Jul–Sep 2025, 91.1% in Oct–Dec 2025, 93.3% in Jan–Mar 2026, 98.9% in Apr–Jun 2026 and 96.8% in Jul–Sep 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights100.0%
- Oct–Dec 202592 flights91.1%
- Jan–Mar 202690 flights93.3%
- Apr–Jun 202691 flights98.9%
- Jul–Sep 202662 flights96.8%
Scale runs 85% to 100%.
By weekday, OO 4099 ranged from 92.3% on Friday to 98.1% on Monday. With about 52 flights behind each day, a spread of 6 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late OO 4099 runs when it is late
OO 4099 often beats the schedule: 211 of 363 completed flights, 58%, arrived 15 minutes or more early. The 17 late arrivals split 6 under half an hour, 3 between 30 and 60 minutes, and 8 an hour or more.
- 15+ min early211 flights58.1%
- Within 15 min135 flights37.2%
- 15–29 min late6 flights1.7%
- 30–59 min late3 flights0.8%
- 1–2 hours late6 flights1.7%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 363 completed flights by arrival against schedule.
A late pushback is often recovered here: of 28 departures that left 15 minutes late or more, 13 still arrived on time. Only 2 left on time and still arrived late.
The worst days
Worst days for OO 4099
The latest arrival of the period was on 30 December 2025, 2 hours 28 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 |
|---|---|---|
| 30 December 2025 | 2 hours 28 minutes | Carrier |
| 1 January 2026 | 2 hours 22 minutes | Extreme weather |
| 20 December 2025 | 1 hour 58 minutes | Carrier |
| 17 October 2025 | 1 hour 29 minutes | Extreme weather |
| 8 October 2025 | 1 hour 28 minutes | Carrier |
Delay causes
Why OO 4099 runs late
Carrier accounts for 71% of the 1,092 delay minutes carriers reported here, and the remaining four split what is left.
- 71%Carrier
- 28%Extreme weather
- 1%National Airspace System
Extreme weather accounts for 28% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 4.6 times the usual weather exposure. The split is drawn from 1,092 delay minutes reported on OO 4099.
Cancellations are rare at 0.55%, 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 2.2% 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.
OO 4099 is not only a LAX to RNO flight. It also flew RNO to LAX (365 flights, 92.0% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 365 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| RNO to LAX | 365 | 92.0% | 54 min | 0.55% | A+ |
What to do with this
Booking OO 4099
For a booking, OO 4099 has one of the better records a US domestic flight can show: 95.3% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- LAX to RNO, every carrier and departure
- RNO to LAX, the return direction
- SkyWest Airlines 4126 on the same route89.4%
- SkyWest Airlines 3929 on the same route88.7%
- SkyWest Airlines 5410 on the same route94.8%
- Los Angeles International (LAX) 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.