Route reliability record

AUS→DEN

Austin to Denver

Flights: 5,509
Period: September 2025 to August 2026
Distance: 775 mi
Carriers: 4

This route lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 5,509 AUS to DEN flights, of which United Airlines flew 1,885 at 85.7% on time.

Best time to fly AUS to DEN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 92.9% of the time and Tuesday flights 84.5%, against 78.9% for the route overall.

United Airlines is the most reliable of the four carriers covered here at 85.7% on time across 1,885 flights.

On time

78.9%

Arrivals under 15 minutes late, of 5,455 completed flights

Avg delay

63 min

Across delayed arrivals only, not all flights

Cancelled

0.64%

National rate is 1.89%

Best carrier

United

85.7% on time across 1,885 flights

These figures cover 5,509 flights between September 2025 and August 2026. The median arrival is 7 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.

Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Carrier by carrier

Which airline is most reliable on AUS to DEN

The choice of carrier is not cosmetic here. United Airlines arrives on time 85.7% of the time; Southwest Airlines manages 72.4%. Sample sizes sit next to every figure, because a two-point gap across 2,402 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
United Airlines	1,885	85.7%	72 min	0.69%	A+
Frontier Airlines	606	83.3%	76 min	0.66%	B+
SkyWest Airlines	616	78.9%	78 min	0.65%	B+
Southwest Airlines	2,402	72.4%	54 min	0.58%	C+

The spread between United and Southwest is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

Flight by flight

Flights on AUS to DEN

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Best ways to make this trip

The most reliable ways to fly Austin to Denver

Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.

Most reliable ways to fly from AUS to DEN
Option	Airline	Success	On time	Cancelled	Best departure	Most punctual flight
1. AUS → DENAustin to Denver	United Airlines	85.1%	85.7%	0.69%	5am–8am, Tue	UA 779 11:27
2. AUS → DENAustin to Denver	Frontier Airlines	82.8%	83.3%	0.66%	8am–11am, Sun	F9 1815 06:45
3. AUS → DENAustin to Denver	SkyWest Airlines	78.4%	78.9%	0.65%	5am–8am, Sat	—
4. AUS → DENAustin to Denver	Southwest Airlines	72.0%	72.4%	0.58%	5am–8am, Tue	—

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against 13 points between the best and worst carrier.

5am–8am1,127 flights92.9%
8am–11am909 flights87.5%
11am–2pm1,048 flights87.5%
2pm–5pm838 flights69.8%
5pm–8pm1,158 flights61.1%
8pm–5am429 flights67.8%

Scale runs 55% to 100%.

The 5pm–8pm window is where this operation falls apart: 61.1% on time, against 92.9% 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 5pm–8pm window is the busiest, with 1,158 flights scheduled in it.

Explore

Filter AUS to DEN by airline, time, month and day

Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.

On AUS to DEN, the best departure window is 5am–8am at 92.9% on time and the worst is 5pm–8pm at 61.1%, a wide gap of 31.8 points. All US flights leaving 5am–8am ran 89.3%.

5–8am92.9%
8–11am87.5%
11am–2pm87.5%
2–5pm69.8%
5–8pm61.1%
8pm–5am67.8%

best all US flightsScale 55% to 95%.

Across the year

When delays peak on this route

This route's year swings by 13 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.January best, June worst

June is the worst month at 72.4% on time, 13 points below January, the best at 85.4%. 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. July was the busiest month here, with 543 flights.

Across the week, Tuesday is the strongest day at 84.5% on time and Friday the weakest at 76.2%, a spread of 8 points.

Delay causes

Why this route gets delayed

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 72,000 reported delay minutes.

Late-arriving aircraft
41%
National Airspace System
28%
Carrier
26%
Extreme weather
5%
Security
0%

41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 72,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 72,461 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.9% on time here.

Cancellations are rare at 0.64%, below the national 1.89% 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 actually costs

7.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, 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.

The return leg runs 76.2% on time across 5,486 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 5,509 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

Work out the risk of missing a connection in DEN after this flight

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.4% on time and June 72.4%, a swing of 13 points. If the dates move at all, move them out of June before you think about anything else. 5,455 completed flights over 12 months sit behind that.

Common questions

AUS to DEN questions

How often is AUS to DEN delayed?

About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.1% of the 5,509 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on AUS to DEN?

United Airlines leads at 85.7% on time across 1,885 flights. Southwest Airlines is at the other end on 72.4%, a gap of 13 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on AUS to DEN?

The 5am–8am departure window is the strongest at 92.9% on time. The 5pm–8pm window is the weakest at 61.1%, 32 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are June delays on AUS to DEN?

June is the weakest month at 72.4% on time, compared with 85.4% in January. Across the year that is 13 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. AUS to DEN and DEN to AUS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Embed AUS to DEN’s on-time badge on your site

Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.

<iframe src="https://delayatlas.com/embed/route/aus-den" width="320" height="132" style="border:0;max-width:100%" loading="lazy" title="AUS to DEN on-time record"></iframe>
<p style="font:12px/1.4 sans-serif;margin:4px 0 0">AUS to DEN flight delay statistics from <a href="https://delayatlas.com/routes/aus-to-den">DelayAtlas</a></p>

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.