Flight number record

OO 4135

SkyWest Airlines · Salt Lake City to Eugene

Route: SLC → EUG
Departs: 10:45
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 4135, 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 4135 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 an hour. That rests on 365 flights, with a median arrival 5 minutes early.

Set against the rest of the country, OO 4135's record is 15 points better than the US average of 77.6%. That gap is worth roughly 150 fewer late arrivals for every thousand flights.

On time

92.6%

Arrivals under 15 minutes late, of 365 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

1 hour+ late

2.5%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 5 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 4135 flies

OO 4135 flies SLC to EUG without a single fixed slot. Its most common scheduled departure was 10:45, used on 219 of 365 flights, with 10:55 (59 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 10:45219 flights60.0%
Departs 10:5559 flights16.2%

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 10:45 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and OO 4135 runs 9 points better at 92.6%. 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 4135 next to SLC to EUG

Every carrier on SLC to EUG combined arrived on time 93.5% of the time across 739 flights, so OO 4135 is about level with it. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 14 points.

OO 4135 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 4135	365	92.6%	58 min	0.00%	A+
All SkyWest Airlines on SLC–EUG	739	93.5%	58 min	0.00%	A+
All carriers on SLC–EUG	739	93.5%	58 min	0.00%	A+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 4135 quarter by quarter

OO 4135 did not run the same all year. Its best quarter was Jul–Sep 2025 at 98.9% on time and its weakest Apr–Jun 2026 at 86.8%, a swing of 12 points on roughly 91 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 202592 flights98.9%
Oct–Dec 202592 flights94.6%
Jan–Mar 202690 flights90.0%
Apr–Jun 202691 flights86.8%

Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, OO 4135 ranged from 86.5% on Wednesday to 96.2% on Tuesday. 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 4135 runs late

One category carries most of the weight here. Carrier accounts for 90% of the 1,576 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
90%
National Airspace System
6%
Extreme weather
5%

The largest share of delay minutes, 90%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,416 of the 1,576 delay minutes reported here. The split is drawn from 1,576 delay minutes reported on OO 4135.

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 2.5% 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 618 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.

OO 4135 is not only a SLC to EUG flight. It also flew EUG to SLC (310 flights, 92.9% 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 4135
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
EUG to SLCthin sample	310	92.9%	52 min	0.00%	A+

What to do with this

Booking OO 4135

For a booking, OO 4135 has one of the better records a US domestic flight can show: 92.6% on time and 0.00% 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