Flight number record

OO 4121

SkyWest Airlines · Austin to McAllen

Route: AUS → MFE
Departs: 15:15
Flights: 269
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 4121, 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 4121 lands a B+, 2 points better than the national rate of 77.6%. About one flight in five 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 269 flights, with a median arrival 3 minutes early.

On time

79.5%

Arrivals under 15 minutes late, of 268 completed flights

Avg delay

70 min

Across delayed arrivals only, not all flights

Cancelled

0.37%

National rate is 1.81%

1 hour+ late

7.8%

National rate is 8.1%

These figures cover 269 flights between July 2025 and June 2026. The median arrival is 3 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 4121 flies

OO 4121 flies AUS to MFE without a single fixed slot. Its most common scheduled departure was 15:15, used on 95 of 269 flights, with 15:25 (32 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 15:1595 flights35.3%
Departs 15:2532 flights11.9%

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 15:15 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and OO 4121 runs 7 points better at 79.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

OO 4121 next to AUS to MFE

Every carrier on AUS to MFE combined arrived on time 82.7% of the time across 1,032 flights, so OO 4121 is 3 points behind it. Across its whole network SkyWest Airlines managed 79.0%, close to this flight's figure.

OO 4121 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 4121thin sample	269	79.5%	70 min	0.37%	B+
All SkyWest Airlines on AUS–MFE	1,032	82.7%	80 min	0.39%	B+
All carriers on AUS–MFE	1,032	82.7%	80 min	0.39%	B+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 4121 quarter by quarter

Quarter by quarter OO 4121 held fairly steady: 76.1% in Jul–Sep 2025, 84.4% in Oct–Dec 2025, 78.0% in Jan–Mar 2026 and 79.3% 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 flights76.1%
Oct–Dec 202577 flights84.4%
Jan–Mar 202642 flights78.0%
Apr–Jun 202658 flights79.3%

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, OO 4121 did best on Saturday at 86.4% on time and worst on Tuesday at 69.2%. Each day rests on about 38 flights, so a gap of 17 points is worth noticing but could still narrow in another year.

Delay causes

Why OO 4121 runs late

One category carries most of the weight here. Carrier accounts for 76% of the 3,863 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
76%
National Airspace System
16%
Extreme weather
8%

The largest share of delay minutes, 76%, 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 2,927 of the 3,863 delay minutes reported here. The split is drawn from 3,863 delay minutes reported on OO 4121.

Cancellations are rare at 0.37%, 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

7.8% 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 same number turns up on three other city pairs in the data, including MFE to AUS (123), DTW to MSN (18) and DTW to IND (1), but none flew often enough under OO 4121 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to AUS to MFE only.

One caution: this is a thin sample. 269 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 4121

For a booking, read OO 4121 as 79.5% on time with 0.37% cancelled over 269 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