Carrier route record

F9LAS→STL

Frontier Airlines · Las Vegas to St. Louis

Flights: 295
Period: July 2025 to June 2026
Share of route: 14%
Carriers: 2

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.

Frontier on LAS to STL earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 295 flights, with a median arrival 15 minutes early.

Set against the rest of the country, Frontier's LAS to STL record is 9 points better than the US average of 77.6%. That gap is worth roughly 89 fewer late arrivals for every thousand flights.

On time

86.5%

Arrivals under 15 minutes late, of 288 completed flights

Avg delay

85 min

Across delayed arrivals only, not all flights

Cancelled

2.03%

National rate is 1.81%

Whole route

79.4%

Every carrier on LAS to STL, 2,073 flights

These figures cover 295 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.

Carrier by carrier

Frontier against every carrier on LAS to STL

Frontier flew 295 of the 2,073 flights on LAS to STL, about 14% of it. Its 86.5% on time is 7 points better than the route as a whole, which runs 79.4%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Frontier at 86.5% to Southwest at 78.2%.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on LAS to STL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlines (this page)thin sample	295	86.5%	85 min	2.03%	A
Southwest Airlines	1,778	78.2%	54 min	0.17%	B+

Departure window

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am56 flights91.1%
8am–11am97 flights86.2%
11am–2pm30 flights80.0%
2pm–5pm112 flights86.1%
5pm–8pm—
8pm–5am—

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

The weak window here is the middle of the day, not the evening: 11am–2pm runs 80.0% on time against 91.1% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 2pm–5pm window is the busiest, with 112 flights scheduled in it.

Across the year

Frontier on LAS to STL through the year

Jul–Sep 202566 flights87.7%
Oct–Dec 202581 flights90.0%
Jan–Mar 202673 flights88.9%
Apr–Jun 202675 flights78.9%

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

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 86.5% on time across 295 flights.

Frontier on LAS to STL did not run the same all year. Its best quarter was Oct–Dec 2025 at 90.0% on time and its weakest Apr–Jun 2026 at 78.9%, a swing of 11 points on roughly 74 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.

Across the week, Sunday is the strongest day at 90.7% on time and Monday the weakest at 80.3%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Carrier accounts for 52% of the 3,323 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
52%
Late-arriving aircraft
40%
National Airspace System
8%

40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 3,323 reported delay minutes here, that single category outweighs weather by 40 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 3,323 reported delay minutes.

The largest share of delay minutes, 52%, 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 1,737 of the 3,323 delay minutes reported here.

Cancellations sit at 2.03% against a national 1.81%, which is ordinary. Diversions add another 0.34%.

Connections and stage length

What a delay here 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 an hour and a half, which a normal layover absorbs.

The 1,371 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.

The return leg is a different operation and performs like one: it runs 78.3% on time across 295 flights, 8 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 8 points of difference.

One caution: this is a thin sample. 295 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 Frontier on LAS to STL

Put together: treat all of this as provisional. 295 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 86.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 288 completed flights over 12 months sit behind that.

Where to go next

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