Flight number record

OO 5388

SkyWest Airlines · Denver to Helena

Route: DEN → HLN
Departs: 11:30
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 5388, 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 5388 lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 365 flights, with a median arrival 5 minutes early.

Set against the rest of the country, OO 5388's record is 5 points better than the US average of 77.6%. That gap is worth roughly 49 fewer late arrivals for every thousand flights.

On time

82.5%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

69 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

1 hour+ late

6.6%

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 5388 flies

OO 5388 flies DEN to HLN without a single fixed slot. Its most common scheduled departure was 11:30, used on 139 of 365 flights, with 11:55 (49 flights) and 11:20 (37 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:30139 flights38.1%
Departs 11:5549 flights13.4%
Departs 11:2037 flights10.1%

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 11:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and OO 5388 runs 4 points better at 82.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

OO 5388 next to DEN to HLN

Every carrier on DEN to HLN combined arrived on time 78.9% of the time across 844 flights, so OO 5388 is 4 points ahead of it. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 4 points.

OO 5388 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 5388	365	82.5%	69 min	0.27%	B+
All SkyWest Airlines on DEN–HLN	844	78.9%	73 min	1.07%	B
All carriers on DEN–HLN	844	78.9%	73 min	1.07%	B
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 5388 quarter by quarter

OO 5388 did not run the same all year. Its best quarter was Oct–Dec 2025 at 87.8% on time and its weakest Jul–Sep 2025 at 77.8%, a swing of 10 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 flights77.8%
Oct–Dec 202592 flights87.8%
Jan–Mar 202690 flights81.1%
Apr–Jun 202691 flights83.5%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, OO 5388 did best on Tuesday at 90.6% on time and worst on Wednesday at 76.0%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why OO 5388 runs late

One category carries most of the weight here. Carrier accounts for 57% of the 4,360 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
57%
Late-arriving aircraft
22%
National Airspace System
11%
Extreme weather
9%

The largest share of delay minutes, 57%, 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 2,507 of the 4,360 delay minutes reported here. The split is drawn from 4,360 delay minutes reported on OO 5388.

Cancellations are rare at 0.27%, 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

6.6% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.

The 594 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.

Every one of the 365 flights under OO 5388 in the data flew DEN to HLN. 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. 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.

What to do with this

Booking OO 5388

For a booking, read OO 5388 as 82.5% on time with 0.27% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular 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