Flight number record

OO 4037

SkyWest Airlines · Hailey to Salt Lake City

Route: SUN → SLC
Departs: 07:30
Flights: 363
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4037, 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 4037 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 21 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 4.1 hours. That rests on 363 flights, with a median arrival 19 minutes early.

Set against the rest of the country, OO 4037's record is 21 points better than the US average of 77.3%. That gap is worth roughly 208 fewer late arrivals for every thousand flights.

On time

98.1%

Arrivals under 15 minutes late, of 360 completed flights

Avg delay

244 min

Across delayed arrivals only, not all flights

Cancelled

0.83%

National rate is 1.89%

1 hour+ late

1.4%

National rate is 8.3%

These figures cover 363 flights between September 2025 and August 2026. The median arrival is 19 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.

Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Schedule

When OO 4037 flies

OO 4037 flies SUN to SLC without a single fixed slot. Its most common scheduled departure was 07:30, used on 155 of 363 flights, with 07:25 (62 flights) and 07:15 (60 flights) next.

Departs 07:30155 flights42.7%
Departs 07:2562 flights17.1%
Departs 07:1560 flights16.5%

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 07:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and OO 4037 runs 9 points better at 98.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Against the route

OO 4037 next to SUN to SLC

Every carrier on SUN to SLC combined arrived on time 93.8% of the time across 1,078 flights, so OO 4037 is 4 points ahead of it. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 19 points.

OO 4037 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 4037thin sample	363	98.1%	244 min	0.83%	A+
All SkyWest Airlines on SUN–SLC	1,078	93.8%	112 min	0.74%	A+
All carriers on SUN–SLC	1,078	93.8%	112 min	0.74%	A+
SkyWest Airlines, whole network	855,406	78.7%	88 min	1.79%	B

Across the year

OO 4037 quarter by quarter

Quarter by quarter OO 4037 held fairly steady: 100.0% in Jul–Sep 2025, 97.8% in Oct–Dec 2025, 97.7% in Jan–Mar 2026, 97.8% in Apr–Jun 2026 and 98.4% in Jul–Sep 2026. A spread of 2 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 flights97.8%
Jan–Mar 202690 flights97.7%
Apr–Jun 202689 flights97.8%
Jul–Sep 202662 flights98.4%

Scale runs 90% to 100%.

By weekday, OO 4037 ranged from 96.1% on Thursday to 100.0% on Sunday. With about 52 flights behind each day, a spread of 4 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late OO 4037 runs when it is late

OO 4037 often beats the schedule: 269 of 360 completed flights, 75%, arrived 15 minutes or more early. When OO 4037 is late it tends to be very late: 5 of its 7 late arrivals were an hour or more behind, and 4 were two hours or more.

15+ min early269 flights74.7%
Within 15 min84 flights23.3%
15–29 min late1 flights0.3%
30–59 min late1 flights0.3%
1–2 hours late1 flights0.3%
2+ hours late4 flights1.1%

Scale runs 0% to 100%.

Share of 360 completed flights by arrival against schedule.

Only 6 of 360 completed flights left 15 minutes late or more, too few to say how often the time is made up.

The worst days

Worst days for OO 4037

The latest arrival of the period was on 15 December 2025, 12 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.

The latest arrivals of OO 4037 in the period
Date	Arrived late by	Largest filed cause
15 December 2025	12 hours 28 minutes	Carrier
11 December 2025	9 hours 15 minutes	Carrier
16 January 2026	2 hours 35 minutes	Extreme weather
22 April 2026	2 hours 22 minutes	Extreme weather
16 April 2026	1 hour 1 minute	Carrier

Delay causes

Why OO 4037 runs late

Carrier accounts for 81% of the 1,709 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
81%
Extreme weather
17%
National Airspace System
2%

Extreme weather accounts for 17% 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 2.8 times the usual weather exposure. The split is drawn from 1,709 delay minutes reported on OO 4037.

Cancellations are rare at 0.83%, 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 1.4% 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.

Every one of the 363 flights under OO 4037 in the data flew SUN to SLC. The number was not reused on any other city pair, which makes this a clean record of one route.

One caution: this is a thin sample. 363 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 4037

For a booking, OO 4037 has one of the better records a US domestic flight can show: 98.1% on time and 0.83% 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures