Carrier route record

F9AUS→DEN

Frontier Airlines · Austin to Denver

Flights: 549
Period: July 2025 to June 2026
Share of route: 10%
Carriers: 4

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

Frontier on AUS to DEN earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 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 549 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,915 at 82.7% on time.

Set against the rest of the country, Frontier's AUS to DEN record is 7 points better than the US average of 77.6%. That gap is worth roughly 72 fewer late arrivals for every thousand flights.

On time

84.8%

Arrivals under 15 minutes late, of 545 completed flights

Avg delay

92 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

Whole route

78.4%

Every carrier on AUS to DEN, 5,310 flights

These figures cover 549 flights between July 2025 and June 2026. The median arrival is 12 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 AUS to DEN

Frontier flew 549 of the 5,310 flights on AUS to DEN, about 10% of it. Its 84.8% on time is 6 points better than the route as a whole, which runs 78.4%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Frontier at 84.8% to Southwest at 72.7%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 82.7% of the time; Southwest Airlines manages 72.7%. Sample sizes sit next to every figure, because a two-point gap across 2,356 flights means less than a ten-point one.

On-time performance by carrier on AUS to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlines (this page)	549	84.8%	92 min	0.55%	B+
United Airlines	1,915	82.7%	69 min	1.20%	B
SkyWest Airlines	490	81.5%	70 min	0.61%	B+
Southwest Airlines	2,356	72.7%	56 min	0.59%	C+

United leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

Frontier flight numbers on AUS to DEN

F9 181506:4586.2% · 308 flights

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 12 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am265 flights86.7%
8am–11am88 flights89.7%
11am–2pm35 flights82.9%
2pm–5pm23 flights—
5pm–8pm6 flights—
8pm–5am132 flights77.9%

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

Book the morning departure. Flights leaving between 8am–11am arrive on time 89.7% of the time, against 77.9% for the overnight window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 265 flights scheduled in it.

Across the year

Frontier on AUS to DEN through the year

Darker means more delays. Figures are on-time percentages.November best, July worst

July is the worst month at 73.3% on time, 23 points below November, the best at 95.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 71 flights.

Across the week, Wednesday is the strongest day at 90.2% on time and Saturday the weakest at 76.1%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 7,604 reported delay minutes.

Carrier
41%
Late-arriving aircraft
38%
Extreme weather
11%
National Airspace System
10%

38% 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 7,604 reported delay minutes here, that single category outweighs weather by 3 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 7,604 reported delay minutes.

The largest share of delay minutes, 41%, 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 3,147 of the 7,604 delay minutes reported here.

Cancellations are rare at 0.55%, 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 stage length

What a delay here costs

5.7% 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 775 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 72.3% on time across 550 flights, 13 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 13 points of difference.

One caution: this is a thin sample. 549 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 AUS to DEN

Put together: treat all of this as provisional. 549 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 84.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 545 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