Flight number record

OO 4099

SkyWest Airlines · Los Angeles to Reno

Route: LAX → RNO
Departs: 08:20
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 77.6%. When something does go wrong the average delay runs about an hour. That rests on 365 flights, with a median arrival 15 minutes early.

Set against the rest of the country, OO 4099's record is 18 points better than the US average of 77.6%. That gap is worth roughly 177 fewer late arrivals for every thousand flights.

On time

95.3%

Arrivals under 15 minutes late, of 363 completed flights

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

1 hour+ late

1.9%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 15 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 OO 4099 flies

OO 4099 flies LAX to RNO without a single fixed slot. Its most common scheduled departure was 08:20, used on 114 of 365 flights, with 09:59 (41 flights) and 09:40 (38 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:20114 flights31.2%
Departs 09:5941 flights11.2%
Departs 09:4038 flights10.4%

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 08:20 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, 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.

Against the route

OO 4099 next to LAX to RNO

Every carrier on LAX to RNO combined arrived on time 88.1% of the time across 2,494 flights, so OO 4099 is 7 points ahead of it. SkyWest flew 2,037 flights on the same city pair under all its flight numbers, including this one, and those ran 90.8% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 16 points.

OO 4099 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 4099	365	95.3%	59 min	0.55%	A+
All SkyWest Airlines on LAX–RNO	2,037	90.8%	65 min	0.34%	A+
All carriers on LAX–RNO	2,494	88.1%	59 min	0.44%	A+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 4099 quarter by quarter

Quarter by quarter OO 4099 held fairly steady: 97.8% in Jul–Sep 2025, 91.1% in Oct–Dec 2025, 93.3% in Jan–Mar 2026 and 98.9% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights97.8%
Oct–Dec 202592 flights91.1%
Jan–Mar 202690 flights93.3%
Apr–Jun 202691 flights98.9%

Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, OO 4099 ranged from 90.4% on Friday to 100.0% on Monday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why OO 4099 runs late

One category carries most of the weight here. Carrier accounts for 67% of the 1,006 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.

Carrier
67%
Extreme weather
31%
National Airspace System
2%

Extreme weather accounts for 31% 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 5.0 times the usual weather exposure. The split is drawn from 1,006 delay minutes reported on OO 4099.

Cancellations are rare at 0.55%, below the national 1.81% 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 1.9% 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.

OO 4099 is not only a LAX to RNO flight. It also flew RNO to LAX (363 flights, 91.1% 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.

Other routes flown as OO 4099
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
RNO to LAXthin sample	363	91.1%	53 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.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures