Carrier route record

F9DEN→AUS

Frontier Airlines · Denver to Austin

Flights: 550
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 DEN to AUS sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 550 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,914 at 79.9% on time.

United Airlines is the most reliable of the three carriers covered here at 79.9% on time across 1,914 flights.

On time

72.3%

Arrivals under 15 minutes late, of 545 completed flights

Avg delay

63 min

Across delayed arrivals only, not all flights

Cancelled

0.73%

National rate is 1.81%

Whole route

76.1%

Every carrier on DEN to AUS, 5,301 flights

These figures cover 550 flights between July 2025 and June 2026. Beyond the headline rate, 9.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Frontier against every carrier on DEN to AUS

Frontier flew 550 of the 5,301 flights on DEN to AUS, about 10% of it. Its 72.3% on time is 4 points worse than the route as a whole, which runs 76.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from United at 79.9% to Frontier at 72.3%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 79.9% of the time; Southwest Airlines manages 73.5%. Sample sizes sit next to every figure, because a two-point gap across 2,346 flights means less than a ten-point one.

On-time performance by carrier on DEN to AUS
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,914	79.9%	64 min	0.63%	B+
SkyWest Airlines	491	78.5%	80 min	0.61%	B+
Southwest Airlines	2,346	73.5%	56 min	0.55%	C+
Frontier Airlines (this page)	550	72.3%	63 min	0.73%	C+

United leads Southwest by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

Frontier flight numbers on DEN to AUS

F9 289021:0064.5% · 317 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 26 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am77 flights89.6%
8am–11am15 flights—
11am–2pm10 flights—
2pm–5pm48 flights78.7%
5pm–8pm128 flights75.6%
8pm–5am272 flights63.6%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 63.6% on time, against 89.6% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 272 flights scheduled in it.

Across the year

Frontier on DEN to AUS through the year

Darker means more delays. Figures are on-time percentages.February best, August worst

August is the worst month at 52.8% on time, 38 points below February, the best at 90.9%. 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 83.6% on time and Saturday the weakest at 66.2%. 17 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. Late-arriving aircraft accounts for 43% of the 9,481 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.

Late-arriving aircraft
43%
Carrier
37%
National Airspace System
15%
Extreme weather
5%

43% 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 9,481 reported delay minutes here, that single category outweighs weather by 8 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 9,481 reported delay minutes.

The largest share of delay minutes, 37%, 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 3,500 of the 9,481 delay minutes reported here.

Cancellations are rare at 0.73%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

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 84.8% on time across 549 flights, 13 points above 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. 550 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 DEN to AUS

Put together: treat all of this as provisional. 550 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 72.3% 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